Tree commitment phobia

I really need "bones" in the backyard. Specifically, trees. There's little shade to be had and what there is comes from two ugly trees on their last legs. I need to screen out the electrical guy wire that slices diagonally through the back half of the yard (the joys of being on an easement--more space, but weird utility equipment issues). Also, since we're on a cul-de-sac, the entire backyard comes to an awkward point in the back corner, and it's all contained by a featureless blank fence with no greenery around. Tree, large shrubs, vertical accents are much needed. So why am I so skittish about buying trees? It scares me. I'm afraid of buying the wrong ones, by which I mean ones I won't like or ones that will grow either too slowly or too fast, both of which have their problems... And planting them, sheesh! That's a whole 'nother ball of wax. What if I plant them in the wrong spot? What if my idea of "full sun" isn't the tree's idea? What if I plant them too close together? What if they just look ugly? It's enough to make you miss the bamboo...almost... okay, no. Nothing's that scary. And besides, trees are going on sale all over town because most people don't know this is the ideal time to plant here in Texas. I did get very brave this weekend and bought an arroyo sweetwood tree. Wish me luck actually getting the darn thing in the ground. It keeps raining and I keep dithering...