What do you say to somebody new to Psionics?

[Roxxy]

I have the DSP books, but I'm still new. I'm using a rune magic variant, but all the rules are the same. Aside from basic rules, what are the ins and outs (what is effective, what is not, what to watch out for), and what does a GM have to consider (What sorts of challenges can a Psionic character wreck? I hear Seers can wreck mystery plots by being too good at them.)?

[icefractal]

Make sure to get at least a couple powers that either don't need augmenting or last the whole combat. The good side of augmented blasting powers is that they stay valid (Dissipating Touch is still good at high level, frex), the bad side is that they eat through PP like popcorn, much less efficient than spells like Scorching Ray. So it's useful to have something like Astral Construct, Entangling Ectoplasm, or at high levels Telekinetic Thrust that's more PP-efficient.

Overchannel is like the Natural Spell of Psionics. It's not just about an extra couple dice of damage, it's about accessing specific augments early, which can be like getting higher level spells early.

If you are doing blasting, then at a certain point you want Empower Power; it becomes unambiguously better than straight augmentation.

If you're summoning, then figure out and stat up your commonly used Astral Construct configurations ahead of time.

By DSP, I'm assuming Pathfinder? Not a lot of changes between that and 3.5 Psi, but there are a few:
* Energy Stun no longer has special god-DC.
* Psychic Reformation is awesome, and you should get it via Expanded Power even if you're not a Telepath. Not only useful on yourself, it's fun for the whole party.
* Mind Control is quite good. Actually, it might be worth banning the "multiple targets" augment on that one, because it makes other Telepathy powers sort of obsolete once you have it.
* If you're a Shaper, you get Minor Creation at will. Absolutely the best at low levels.
* Overchannel doesn't stack with Wild Surge, don't get it if you're a Wilder. Also, Wilder is decent, especially at higher levels.
* At high levels, Reach Power allows you to put the badass and normally self-only psionic combat buffs on other people. Highly effective. Mind Switch does this too, but might not work for some powers and requires a trusting relationship with the other character.

I don't think Seers are more plot-derailing than other diviners, although they do have one power (Object Reading, IIRC) that there's no arcane/divine equivalent to.

[Ilorin Lorati]

Like almost any caster, heavily psionic characters can gain access to tools that can complete/trivialize just about any challenge given a modicum of thought and preparation time. The only thing they tend to have a hard time with compared to spellcasters is that they have no reliable way (currently) of handling spirits and the already-dead, and healing requires special builds or Vitalist, which is a class built around empathic healing. However, they tend to do more damage with any thought at all put into building towards damage dealing.

The difference between psionic characters and spellcasters is that psions tend to have a smaller toolbox. Their tools may be more flexible, but the DM will almost always be intimately aware of what those tools are - which isn't the case when dealing with prepared casters. Even spontaneous casters have a larger toolbox.

Psionic characters are also somewhat more prone to "nova" than spellcasters, which means depending on the group a DM may need to be more careful about combats per day or challenges in which the character would use PP, forcing the player to think about how much power they're expending at one time.

As far as advice to you goes: be very patient with the DM if they're new to psionics too. While psionics may be more balanced than spellcasting in many ways, many people think that because psionics does some things better than spellcasting it's "broken", as if spells were a gold standard. Which to many is a fair thing to say simply because most people don't have experience with anything else.