I know how to increase the skills but I don't know how to purposefully raise my Ratings scores.

It would help if you mentioned which game you are referencing. This does not apply to Betrayal.

Oh, my mistake I thought this was a board about Betrayal at Krondor or it's sequel my bad sorry about that.

It is about all three series games. They do not all have the same mechanics.

You can't raise attributes per say, they do go up over time in Betrayal. There is also a quest in the mines with the goblins that raises them.

Thank you that was very helpful.

Hello,

the Kobold quest increases maximum health and stamina.

According to "MR KNOWITALL'S GUIDE TO BETRAYAL AT KRONDOR", those also increase while you sleep at every 30 in-game days. I think that's not fully correct, the passing of game-time is sufficient.

Time passes slowly whenever you walk a step, how much depends on the step size you've chosen in the settings.
More time passes when you leave a "map region" to enter another one.
Even more time passes when you click on the sunset at Highcastle, you'll travel to Cutter's Gap and back for 6 days.
Time passes also while you rest / sleep.
When standing still, inside traps and during battles, in shops and cities, as well as in dialogues, no game time passes.
Remember that 1 ration per person is consumed every midnight, so "boosting" your health/stamina comes at a cost.

Speed cannot be increased.

Strength increases during melee combat on successful hits (so can be "trained" easily in one of the "endless" combats), and can be increased dramatically at a magical well SE of Elvandar, consuming Fadamor's Formula potions. Have only one at a time in Owyn's inventory when clicking on the well unless using the bugged version 1.02.

Keep in mind that the upper limits are 255, and they do "wrap around". The Guarda Revanche sword can get "too strong" and increase instead of decrease the enemy's health this way.

The "selectable" skills (on the swords) can all be increased to 100% easily with enough patience (and doing so has no undesireable effects), except assessment, which does not increase by usage in combat. There are 3 opportunities to learn it from NPCs, and a book exists, however. The less skills are selected at usage time, the more those increase, so it is best to (de-)select skills between different actions. Only some skills (barding & lockpicking, I think) increase also for inactive spectators.