So, I decided to finally start Fallout 1. From all titles in the series I have only played Fallout Tactics (and enjoyed it) about 8-9 years ago.

I have some questions and feel free to throw any general tips you think I should know.

1. I don't like tweaking my games much with mods, I prefer to play games as the developers made them (minus the nasty bugs). I have downloaded High Resolution Patch (will play in 1920x1080 with Scaling X2), is there anything else I MUST download to enjoy the game as it should be enjoyed?

2. I like playing games on higher difficulties as long as "hard" is not "insane" actually. What will Hard game difficulty and Rough combat difficulty bring me in comparison to Normal setting?

3. From the offered characters I like Albert the most, but I like creating my own characters in RPGs. Will I be missing anything from the story if I create my own character instead choosing the offered one?

4. Exploring and turning every rock is probably the most fun thing for me in RPGs. Should I rush to get that water chip ASAP, or do I have time to wander as well?

5. How big the game is aside from main quest(s)? Lots of sidequests of is the game mainquest focused?

1. No.

2. The game is not that hard, even on hard difficulty and tough combat settings.

3. On the contrary. Using your own character is better. The offered characters are just prepared characters with no special parts of story or so.

4. You definitely have time, and you can even prolong that time in the game. Just watch the remaining time (travelling takes a lot of time).

5. The main quest consists only of like 3 things. The side quests however are basis of this game. Through them you learn about the world around.

No. I would argue you don't even need the hi-res mod, but that's a matter of taste. For both Fallout 1 and 2 you don't need any mods for a first-time play. Hard difficulty makes you start with lower skill levels, but not much beyond that, and you can change the difficulty on the fly at any time. I've never actually tried Rough for combat, but I think it lowers your change-to-hit a bit. Overall, the game is not particularly hard, even with the higher settings. No. In fact, I recommend creating your own character. There is a time limit for finding the water chip, so you should attend to that before wandering too much. Once you've accomplished that, you can wander as much as you like for the most part. New players tend to feel some crunch with the water chip time limit, but it's not onerous. Just keep in mind what your objective is and keep an eye out for clues to follow. Fallout 1 is not that big. If you do nothing but follow the main quest you can finish it relatively quickly, but you'll be missing much of the fun IMO. Wandering is very enjoyable and rewarding, and there is no exact linear route to the end, so feel free to explore -- once you've got the water chip.

Keep a few saves at a time so you can restore in case something goes wrong. The game is not super-buggy, but it has quite a bit of scripting, and it's not unheard of for strange things to happen. My system is to keep a DEPARTURE save, which I use every time I leave a marked location, a TRAVEL save, which I use for any encounters that may happen between marked locations, an ARRIVAL save, which I use whenever I first reach a marked location, and one or two GENERAL saves, which I use during my stay at any marked location. If something goes bonkers I can always return to a point in the recent past. You should always save after doing something you don't want to have to do twice, just in case.

Finally, don't ask for help or look at guides unless you really get stuck. You'll be spoiling the fun. You only get one chance to play Fallout for the first time.

That should be the case with any game, not just with Fallout. ;)

Yes, but I think it's especially true for Fallout.

Some side quests tend to get broken if you do things different from what developers expect you to do, not a plus in my book.
For example in Junktown I wanted to help Killian get rid of Gizmo by killing him and peacefully solve the "Bust the Skulz gang" quest. In pipboy I got only "Bust the Skulz gang" quest as active. I talked that girl member of the gang into leaving the gang. Then I went and asked how much Gizmo will pay me for killing Killian. After he said the number I decided to walk away, he wouldn't let me a I killed him and his bodyguard. I got 500XP for killing Gizmo but after that all other quests got broken. "Save Trish" and "Help Saul" didn't trigger right, I convinced Sherry to testify against the Skulz but I couldn't take her to Lars. After that I killed entire Skulz gang but the quest still remains active becasue when I go to talk to Lars he says that I screwed up by killing Gizmo before I got the evidence and that I should leave town. I wouldn't mind if not doing things the proper order fucks one quest, but if that fucks up all the other quest that is just bad.

I picked Sneak, Lockpick and Barter as my "major skills" (those that get up two points when you spent one skill point on them), but so far it seems like my choice was wrong as Sneak seems totally useless, I only needed Lockpick once. Barter was a good choice, I'm loaded with caps.

Some new Q's:
1. What is the best way to use First Aid Kit and Lockpicks? To put them in hand and use from there (like with weapons) or pick the proper option from Skilldex?
2. Are food and drinks useful for anything or should I just sell all that? So far I only know that funny looking Fruit heals some HP, other stuff (food on stick, nuke cola) doesn't give any effect. My Outdoorsman is currently at 32% if that means anything.
3. My action points are at 8 from the start of the game, it there any way to improve this, and if yes how? I'm currently Level 4 (close to reaching lvl5) if that means anything.

1.- You need to put in on a hand and use it on the target, or you can right click in the target to get the option of use an item of your inventory.

2.- Their are useful when your are traveling form the wastelands, for prevent random deshidrataion and loss of health, and to recruit Dogmeat.

3.- One reached a certain level (sorry, I'm not remember what), you have the option to take a perk that give you an extra action point. Also when you gain access to the bunker of the brotherhood, the doctor here can improve your agility.

Sneak is a very powerful skill in the game; Barter, on the other hand, is one of the most useless as you'll end up with more stuff/caps than you can ever use sooner or later. Most quests can be solved in at least 3 ways: the guns-a-blazing way, the sneaky way, or the talkative way.

For your first question in the OP: as many said, you don't NEED anything to enjoy the game, but installing one of the unofficial patches (like fixt) gets rid of many a bug.

Food heals minor amounts of damage. But food and drinks are mostly for 'flavor', imo.

iirc, action points depend directly on agility. There are perks that can raise it, I think. Or you can cheat and use a character/savegame editor, but I don't recomend that in your first playthroughs.

Edit: I'm not answering other questions because other users have done a fine job answering them.

Keep multiple saves. You can ruin your game in many ways.
Especially around the glow.

Some of the quests get broken because there are bugs here and there, but there's no one way the developers wanted you to play the game. One of the reasons the game is so enduring is that it can be a rather different experience depending on your character's strengths and weaknesses. You can even play a character with minimal INT and you'll get special dialogue and quest solutions throughout the whole game.

You can get more action points by increasing your Agility (certain drugs will do that too, don't forget), or by taking the Action Boy perk or the Bonus Move perk.

UniversalWolf is, as usual, right and spot-on.

You're a true Classic Fallout Venerable Sage :)

That's a nice way of saying I'm an old guy who has played Fallout for many years. :)

BTW, Bonus Move is arguably better than Action Boy, (BM gives you two action points that can only be used for movement, while AB gives you a single normal action point) but it's definitely better if your character is a melee fighter. Closing with your enemies is crucial in that case.

From what I heard from you guys, that doc from BoS that can upgrade my Agility is my best hope, as I'm more interested in being able to shoot my gun twice in a single round (need at least 2 more AP for that) than moving around.
Me and Dogmeat are currently at Military Base. Water chip has been delivered, so it's (meaningless) exploration time. \o/

If you're using a gun "bonus rate of fire" is the most useful perk.

Military Base is mission impossible at this moment (I'm level 8 and wearing Combat Armor) since those miniguns are making Swiss cheese out of my character. So I killed two guards on the base entrance and with my inventory full of their valuable stuff I'm off to Brotherhood of Steel.
I hope I'll have enough money for doctor's adjustments, that librarian lady has secured next 10 generations with money I have spent on skill books at her store. XD

Next question: What armor has the best Weight-vs-Protection ratio? My carry weight is 150 and I like to have space for loot so I don't have to go back and forth often in order to sell it.