I've gotta say the biggest problem is stated directly in your thread title. "Can't" can be your biggest cause of failure, you can Lucid Dream--anyone can; you just need to put the effort and determination into it. Instead of jumping right into Lucid Dreaming, first try and put your mind in the proper state. Get pumped for it, think of everything you can do, watch movies like Inception, listen to music that inspires you. You'll find that once you're in a more positive state you'll be more likely to succeed.