From what you've said so far, I'll suggest a couple of things. First, neither you nor your DM sound like you're interested in learning new subsystems, so stay away from incarnum, TB, TM, etc. Second, you should mostly stick to rogue. Rogue is by far the best non-casting class in the core, the only one that can stay relevant (not equal, but relevant) in a party of optimized full casters, and is very hard to improve on even with the ability to take any non-core PrC. In particular, there are almost no PrCs that give 8 + Int skills for level so multiclassing almost always hits your utility. There are a variety of dips that can help doing specific things, but rogue 20 is a cromulent build with a lot of advantages. Third, you don't need social skills (Bluff, Diplomacy, Sense Motive) to lead your party OOC. The most important IC element of playing party leader is making sure you can communicate with all members of your party, which means languages, things like telepathic connections, and so on. From what you've said so far, you'll want Search for trapfinding. Disable Device is useful but not as important because once you've found a trap, there are often ways to trigger or destroy it without using Disable Device directly. Other than that, you can pick your favorite skills and run with them.
Combat-wise, you're running TWF with sneak attack as your added damage source. You can choose to emphasize melee or throwing to various extents, but there's not any good reason to limit yourself to one or the other, which means your basic feats are TWF, ITWF, Quick Draw, and Weapon Finesse. Weapon Finesse is less important than usual because your stats are insane, but it's still probably good to have. One tactic that works very well for anyone with sneak attack and Quick Draw is tossing flasks of alchemist's fire, acid, or holy water. They hit as ranged touch attacks and add your sneak attack damage, letting you bypass DR on some monsters, target some elemental weaknesses, and deal good damage at range. If you focus on throwing, you'd want to pick up Point Blank Shot, Rapid Shot, Precise Shot, Improved Precise Shot, and some non-core feats, which means multiclassing for extra feats. For melee, you don't really need anything more than the feats I already listed unless you're doing something specific. Improved Initiative and Leadership are good on everyone.
Gloves of the balanced hand (MIC) replace the need for ITWF, but whether they're worthwhile depends on how hard it is to find specific items, how much money your DM gives you, how easy it is to move the other things you need to other slots, and how much you need the extra feat. Generally, I'd give
gloves of dexterity top priority and a
glove of storing only a little less priority over
gloves of the balanced hand. You want a backup bow, a shortbow if you don't pick up martial weapon proficiency somewhere or a longbow if you do. You'll want a
ring of blinking ASAP because it's the easiest way of getting sneak attack at range and has many other excellent benefits. You'll also want some combination of
greater demolition and
truedeath weapon augment crystals (MIC 65-66),
deathstrike bracers (also MIC 93), wands of
golem,
grave, and
vine strike (SC, CAd), and penetrating strike (Du 13) for handling monsters that are immune to sneak attack; potentially some way of defeating concealment if your DM will use that to prevent you from sneak attacking, probably a
crystal mask of visual insight (MIC 92, CP 109) but see also
http://www.minmaxboards.com/index.php?topic=10479.0; and ways of negating DR, where carrying +1 weapons of all three different materials and
lesser truedeath crystals will cover most of what you need to, but there are also a wide variety of other ways to defeat DR. If you want to melee, you really want to get a way to move and full-attack in the same round, Person_Man has a guide at
http://www.giantitp.com/forums/showthread.php?t=103358. There is a lot more, but that's probably enough to absorb for now.
Yes, skill tricks are worth looking into. The ones I favor most in general are Back on Your Feet, Extreme Leap, Nimble Stand, Quick Escape, and Twisted Charge, but others can be useful for specific things.
