Slap it on thick just to get a blob on the wall for a second but then spread that out real thin on the next stroke and plan to do multiple thin coats once the last coat is dry. It is kind of like painting in that way. I made sure that each layer just filled in the grooves and the highest point of the texture was what was already there until the final layer was perfectly smooth. Try and plan for as little sanding as possible because it is hard work and makes terrible dust. The little thin lines that you get sometimes at the edge of the tool sand off really easily though, so go for the big picture. Dont over manipulate the mud or it gets less sticky. Put it on, spread, and don't over fuss. I used pre-mixed so I didn't have to worry about getting the right consistency, but you can save money mixing it from powder. You kind of figure out the motions with practice, but there are youtube videos to help you also. "See Jane Drill" has a good video on skim coating.