There is certainly some merit to being risk averse, but being too afraid to make mistakes can defeat the very purpose of a home. Your home should be about you. It should be a place filled with the things that inspire you, that make you feel safe, creative, energized, fulfilled, and at ease.
Following the rules or taking precautions before buying can lead to some great results, and one should certainly take the usual steps of measuring, price comparing, testing for comfort, etc. But on top of all that, I think we should also take the opportunity to rid ourselves of too many ideas of what a home "should" look like, and stop feeling nervous or afraid about implementing risky ideas.
My favorite tours on Apartment Therapy tend to be those where the owners weren't afraid to use colors boldly, to place art in strange places, or to use objects in new and innovative ways. A bear in the dining room? A swing in the living room? A collection of paint-by-numbers of Gainsborough's "The Blue Boy"? It's these personal touches that really make a home. And these are clear signs of people who went with their gut instead of fearing mistakes.
Personally, I'm using the January Cure as a means of taking some risk. My living room is decked out in lots of cool colors, and I've been thinking for a while that I'd like to add in a dash of red. Now's my chance. For you, maybe it's time to put up that gallery wall. (Nail holes are easy to fix.) Or maybe it's time to do a little painting (Also easy to fix.) If those sorts of risks are too hard or uncertain for you, then work up to them. Resolve to choose one small thing that you've been considering but haven't been sure about and just do it. Try a French press. Get a dish towel in a funky color. Whatever it is, let January be the time to do it.
If it doesn't work out, remember that Craigslist, repurposing, or painting are all options. Hopefully you at least took pleasure in the creative process or the joy of the unexpected, and if the risk pays off, all the better. Either way, hopefully the process will help you to listen to your creative impulses and to approach your surroundings with courage and an open mind.