If you want a full list of tips, there are always of course, FAQs. If you just want a few things to nudge you in the right direction without any spoilers:
1) As has been said many times, the time limit is NOT a concern. I've heard of many players being overly stressed by it. If you're one of those, don't worry. You'd have to really mess up and intentionally waste time to not finish before the limit. DON'T let the timer ruin your fun.
2) Your starting stats are pretty much set in stone. Choose stats you'll want to have at the end of the game. Strength is needed to wear heavier armors (if you want to) so don't go low. Action points are king.... you'll want as many as possible. Later on you're offered perks... some of them only appear if the right stat is high enough. So have high two or three stats relevant fo your character.
3) For skills, tag at least one ranged weapon, maybe even two. Melee somewhat, but especially Unarmed, suck. You might want to tag Trade for better prices. Don't take stealth or pickpocket.
4) You can find a few companions, but be careful when fighting with them. The game has poor AI, and they can easily hit you when shooting at enemies. Stay out of their line of fire, and control what weapons they use so they don't kill you.
5) There are a few good mods out there that can improve numerous features, including the companions. I recommend them.