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