effectively - more effectively - the most effectively
soon - sooner - the soonest
successfully - more successfully - the most successfully
quickly - more quickly - the most quickly
often - more often - the most often
slowly - more slowly - the most slowly
much - more - the most
well - better - the best
Хотя для наречий quickly, often и slowly возможен и второй вариант
quickly - quicker - the quickest
often - oftener - the oftenest
slowly - slower - the slowest