| Cherez |
No hard and fast rules, but the rough procedure would be to find powers that have similar effects and merge them into one power.
For different sorts of powers there would be one base power and all the similar powers' effects would become augments of it. If a class of powers is too broad (like the Energy * damage spells) you would have to buy the more powerful augments with an enhancement.
Every level you would realize a new ability with your powers, and would gain either a new power or number of enhancements to known powers.
This would give Psions more "powers known" in the 3.5 sense, but it would be a higher level of control over a more limited number of effects, reflecting a high mastery of whatever latent powers the character was born with.