Make sure that you truly expect and believe that you're going to be lucid!
When you're RCing, don't just ask yourself if your dreaming and RC like a robot. Stop what you're currently doing, truly believe that this could actually be a dream and expect that you are actully going to breath through your plugged nose or have strangly mutated hands (or whatever RCs you do) and most importently: NEVER EVER say the following: "Oh, it's not a dream..", even after you've done your RCs. If you don't realize that you're dreaming, just keep on with what you were doing before.

You may also want to improve your dream signs. Find a few things that occours often in your dreams and look for it while you're awake. Make sure you do a RC EVERY TIME you experience something that you often experience in your dreams.

I hope any of this helped, and I hope you'll get more lucid soon!