I think you need to stick with it. Don't get discouraged draw out your concept first then execute it. It can just be practice you can even show us and just let us know that you are having a hard time we can offer suggestions etc.

When you get a block it normaly means your eyes are starting to see squares no matter what your doing.

My trick: Few beers [STELLA ARTOIS] with mates & a meal, look at outside life around you...go take some photos or ask mates for ideas.

If none of that works...SLEEP!

Perhaps it is the opposite. You can think of ideas, but you don't know how to render your mind to paper that is a skill in itself.

Spend a bit of time browsing tutorial archives like http://pixel2life.com or http://psdtuts.com looking at the interviews and tutorials until something neat catches your eye. You don't even need to read the tutorial, its usually more inspiring to work it out the effect with out tut help

Create a msn :p