I agree with Brett. Mix and match! Try to work less sleights/tricks, 3 is the golden number. You can't learn everything at the same time, you can't even learn everything sleight there is, there are just too many.
Also, try to mix difficulties. I try to learn difficult, intermediate and easy sleights at the same time. Easier sleights I will pick up faster, but for the more difficult sleights I know I eventually use, the sooner I start, the sooner I will be able to perform them. I would not try to learn just the pass for months at a time while not working on anything else, that would be so boring. But by mixing various difficulties, and rotating them, this gives color to your practice.
You'll get small victories as you succeed on the easier sleights, and it will become more rewarding as you progress to more difficult sleights. Also try to savor your victories, and remember them. They will fuel your motivation. Even partial victories are motivating.
For example, I knew I wanted to perform the pass eventually and I know this one is a life-long achievement, so I got on it as soon as I could, and I practiced it regularly, rotating it with other easier sleights to prevent getting bored/frustrated. Since I knew this one would take me more time to learn, I could be more patient about it, analyzing it more in details, because I knew I could not rush it. I have been working seriously on the pass for a year and a half now, and I was just realizing a few weeks ago how to release the tension in my hands (a small victory even though I am not ready to perform it yet). Well, yesterday I realized what the Professor meant about that left index finger not moving in Revelations (a much bigger victory) and off I am back to practicing... more motivated than ever!
You do not have to like practicing, you have to love it. Make practicing a game, it has to be fun. If you get bored or frustrated, go do something else, and come back to it later. Beware the dark side...
Remember those video games where you just can't beat that boss? And then you would come back the next day, with rest, relaxed, and charged with positive attitude, and you beat it easily?