To the original subject of this thread, I would say that a good solution to the issue of perfectionism is to deal with the fear behind it.
Personally, having a set of rigid goals in place to refer to can dampen feelings of perfectionism as it intensifies. I agree completely with Dorateen here: start with what you, yourself, would enjoy playing first. Set down an outline of your design on paper first, no matter how it is that you work that out. Refer to this outline often, especially when you are venturing outside the bounds of it, so that you can remind yourself of your initial goals. Don't be afraid to explore/expand, but don't do this because you are afraid of leaving material out or in an attempt to make your design as accessible to as large an audience as you can. This is FRUA and you already have an established and interested audience in the community you are already a part of. Don't let what you feel to be your own shortcomings affect your design. If you feel that your creativity with graphics is subpar, explore the vast repository of artwork available. If you need a specific bit of art, ask here. If you think that your design will suffer because you do not have years of experience with the construction kit, remember that all of us here started somewhere... and somewhere was invariably at no experience whatsoever. Lastly, remember that creation is an act of positivity, and even the smallest act is a contribution to the community as a whole. Try starting small and try starting with something that you are afraid of: draw a few combat icons or a map or a wall for importation. Use the toolset to import your work and check it out from within the game. Write a short tale or detail a character from your design and post it here on the forums. You have a built-in group of likeminded folks itching for new bits to enjoy and give you feedback if that is what you feel you need. Ask questions. It doesn't matter a whit that the same questions may have been asked before. Check out one of the numerous designs from the Magic Mirror and try it out... play with it awhile... then open it within the toolset and pick it apart from the inside to see how it was built. If you are uncomfortable on the public forum, choose one of the active posters here and petition them with a private email to have your questions answered. Personally, I've never been a part of a more open and accommodating group of online strangers than FRUAdom has to offer... and FRUAdom has a lot to offer.
To elaborate on the responses here, try joining in on the one-week challenge: even if you just want to make a single encounter of custom creatures with custom artwork or just have a series of text events that tell a bit of a story you've made up, do it. Become part of FRUAdom and create with us.