I started playing UMK3 back in the arcade when it was released, back when everyone basically still played it like MK2. I stopped playing it in the arcades before the new style of play really started, I think in 1999 or so, so I had quit playing it in arcades prob. in late 1996 or sometime in 1997 when the SNES/Genesis/Saturn versions came out and then cemented not playing it in arcades when MKT came to the PSX. I hadn't played it in the arcades until about 6 months ago at the Break where I was so totally unfamiliar with the stick that I looked and felt like a complete beginner. I was a complete pad player for over 10 years at that point, however playing Street Fighter was like riding a bike on stick, that I could still do.
Anyway, on topic(I'll get back to the stick play later)... I've know I've gotten better for a few reasons.
1. I no longer play UMK3 like MK2.
2. I win far more games than I did when I first began truly learning how to play UMK3.
3. I accepted THROWING as a usable technique. Alot of people have problems with it.
4. I started playing better competition and learned from losing till I got better.
5. I am now better on stick than I was on pad.
Regarding stick play. The first thing is to NOT give up. No matter HOW frustrated you get, no matter who you lose to, no matter how many trash talkers you KNOW you can beat with the pad... if you commit to the stick, then commit to it. Lose to those players and just keep playing. Eventually it will click. Eventually you'll beat those players and trust me, b/c I just went through this...it will be that much more gratifying to know they can't beat you on EITHER stick or pad...not that you have to switch to a pad just to beat a certain person.
Finding a "comfortable" position for holding the stick is important, but that will come over time. The more chars you use, you'll notice you will change hand position throughout the game anyway. That will come through time and experience...so though it's important, it's a learning process. Use something comfortable for now, and for most moves, try to execute them from the middle to bottom of the stick(like a lever...closer to the base has the shortest distance to move).
I def. recommend spending time just practicing the execution of moves. If you're a H.Smoke user, practice the spear and TP from BOTH SIDES till you can execute them on command. Practice Run Jabs from both sides. If you need to, use the pad for a round and forget watching the screen...watch your hand and see how your hand works for them, then move the mechanic over to the stick. It will take time but the timing mechanics are the same...the big difference is that you use one hand for buttons instead of 2.
Once you get move execution down, then try practicing combos on a dummy 2nd player. Again,practice from both sides. It won't take too terribly long to get these if you have your move execution down. Overall the move from pad to stick will take some time... a month or more. The big difference is that more options are available to you this way. Instead of limiting wrist movement on a pad to press that left bumper, you have 6 buttons and 5 fingers. Charging moves is easier, etc. I could not perform H.Smoke's combo into aaHP, JK, Air Throw on a pad... the timing was just not there. On stick I can do it. I still can't do Sindel's multi-scream combos on pad, but I can on stick. So to be honest, it is true, I know I've gotten better at UMK3 b/c I got a stick.