I'm by no means a pro, but beyond the lube *which would help with the finger tricks* my recommendation would be to TRY and STAY RELAXED. If you watch a classical pianist's playing, even when they're playing a very complicated section, they're staying as relaxed as possible. That's why you start off SLOW!!!
When you start slow and work up to a certain speed, what you're doing is ingraining the muscle memory to act a certain way. When you stay slow, you maintain a relaxed focus on solving the cube, playing a difficult passage, etc. When you speed up properly, the relaxation stays, but the speed increases. Watch any pro-cuber, and I'm POSITIVE that anyone that has solved it in less than 15 seconds can agree with this - staying relaxed is paramount.
Part of the reason you're not could be the striving for speed, and part could be the cube itself as well. I'd say try and loosen your cube, lube it some and take your time. Practice going slowly as much as you can and gradually increase the speed.
Again, when you align that to playing an instrument: When you play too fast too early, you'll be too tense, the motion won't be natural. You'll make mistakes and mistakes = time missed FIXING mistakes.
Here are 2 examples. One is a complex piano peice. Another is a very fast solve. Compare a couple of things such as breathing, shoulder height/tenseness, wrist stability, etc. It's very very similar. Breathing is WAY more important than you'd think in ANY performance as well, regardless if it's piano, sports, speedcubing, etc.
Arcadi Volodos - Considered one of the WORLD's best classical piansts. He's playing the 3rd movement of the Rachmaninoff's Second concerto *often looked at as one of the hardest peices for piano besides Rachmaninoff's 3rd concerto - which is equally as startling and difficult. (Check out 5:34 and on. Believe it or not, those octaves sections with both hands are BRUTAL to play if you're not relaxed.)
http://youtube.com/watch?v=Jb2LplptbFY& ... ed&search=
The reason I choose this video is because he's not REALLY moving the cube that fast. In actual fact, it's just effecient with his timing but he really isn't moving like crazy.
What is consistant is that he's very fluid with his motion. Very relaxed...
There's a pattern there! lol