After the Fall
Every time you level up, your HP goes up by your CON modifier and your MP goes up by your CHR modifier. If the modifier is negative or zero, then this is ignored.
When you level up you also get 12 leveling points (LP) to spend. For the purpose of spending these points, you must choose what type of build you are leveling up in. The first time you choose a new build (the exception being the one you start with), it costs 12 leveling points.
Feats generally cost 4 LP
Skills generally cost 1 LP if it is trained or 2 if untrained. The LP cost for a skill is doubled for that skill after 6 points have been bought for it. Racial, social or other bonuses do not count against this LP limit for skills. Thus after a skill is increased by LP spending 6 times, the cost for that skill is 2 if trained and 4 if untrained.
The cost to increase MP and HP depends on the class. Their cost double after 20 increases.
The cost to increase BAB depends on the class. Its cost doubles after 5 increases.
The cost to increase Fort, Ref, or will depends on the class. Their cost doubles after 4 increases.
To increase STR, DEX, CON, INT, WIS, or CHR, it cost 10 LP.
Spells cost 3 LP to learn.