After a draft, I always take a long hard look at my team. I find my strengths and weaknesses, identify the occasional "what was I thinking" draft pick as someone droppable if a good waiver opportunity should and figure out which positions are concerns.
Then for the most part I stay put for most of April. I try not to let hot starts and cold starts have any effect on my pre-season rankings. If other managers get impatient with guys that I had ranked higher in the pre-season, I upgrade when they drop them.
Typically, owners make way to many moves early in the season and not enough later. For the most part, April is all about taking chill pills.
"All opinions are not equal. Some are a very great deal more robust, sophisticated and well supported in logic and argument than others."
— Douglas Adams (1952-2001)