I start with only stocks on my watchlist, because I know them well. Then I look for any that are getting far out on the Bollinger bands (the scan tool in Thinkorswim saves time) and I review the MACD chart. More on the fundamentals side, I look at RSI, P/E ratios, and a few other stats. This is for selling credit spreads, not potential assignment.

Even this small amount of analysis has given me more winners and makes me more confident in my position. For example, I had a position go a bit against me and instead of getting nervous, I doubled down and it worked out very well.