I don't have any great tips for avoiding blunders, except for that you should think fast and consider a lot of options, rather than fixate on one plan immediately, and then consider the best way to go about it.
One of the most common errors among mid-tier level players that I see, though, is failing to leave options open. Letting yourself go broke to execute a powerful run without any way of recovering is an easy mistake to make. A lot of people just think "okay, I have this much money, so I can do this," and then do it. Really, the key to running, I find, is making only the most efficient, probing plays, that leave you with the most options for the next turn. If you don't show your hand, so to speak, it usually can force your opponent to play around things that you're not even doing or even just mess up entirely.
I think the avoiding the big, costly misplays can only really be avoided by playing a lot so that you know what to expect. The best way to never make a misplay again is to make it once and remember it. Your Corroder is only going to get shut down once when you have a Faerie in your hand. After that, you play the stupid Faerie.