Newish Rogue: Some gearing, grouping, and skill questions

[medievalerror]

Level 15 rogue here with a few questions regarding the class. First, regarding gearing, I have about 800 plat to my name. I assume my first order of business should be to max out my strength, correct? I am a human rogue with STR currently at 134. Gear-wise I am rocking a Crystalline Spider Fang in my Main Hand and a Black Blade of Tormenting in the off-hand (I wanted a non-piercing weapon that had a decent delay)--I also have a second dagger (Chokidai Spine) that I sometimes drop into my off-hand when things get rough (b/c my 1hs skill is only about 20). My gear (below) is very cheap/lowbie:

Face: Sarnak Hide Mask/Mask of Deception
Earrings: STR +3 earrings (amber?)
Arms: Blackened Alloy
Head: Blackened Alloy Coif
Legs: Giant Scalemail Leggings
Chest: Giant Scalemail Tunic
Wrists: Hero Bracer + Bracer of Erollisi
Feel: Dwarven Work Boots
Waist: Purity Belt
Hands: Iksar Scaled Gloves
Back: Giant Scalemail Cloak
Fingers: Golden Fire Wedding Rings x 2
Empty: Neck & Shoulders

My first question for the forum is, what should I focus on upgrading, or should I simply keep saving for a haste item like FBSS or SCHW? What about my weapons--they are decent, but should I replace one of them prior to armor? Seb Dirk would be ideal of course but that is quite a lot of plat that I won't see for a while---I considered upgrading 1hs to a Crystalline Short Sword.

My second question: Where should I be spending my skill points as I level? I have been trying to keep Sneak/Hide (and backstab of course) maxed. I am also keeping Lockpicking and Sense Traps maxed---am I correct in my assumption that Sense Traps (though it is easy to max) is fairly worthless? I am working on increasing my "Pick Pocket" skill as well though that one is slower going (it is around 50 right now, mostly from pick-pocketing Orc Pawns and using it with groups permission). I was thinking about spending my skill points in increasing 1hs or another weapon skill that I do not readily use at the moment. Where have you other rogues spent your points?

Third question: In groups, even though the role of a rogue seems fairly straightforward (Backstab/Evade/Backstab), I wonder whether there are things I am missing or advice that other rogues wish they knew at lower levels. Any advice here? I want to be sure I am providing the max utility to my group and it seems that every class has little tricks that those new to the class are unaware of and that the wiki/guides do not mention.

Name is Dairk if you ever want to shoot me a message in game. Thanks for your help, all!