f2l can really take a lot of time from your solves. LOOK AHEAD is the most important thing in f2l. when you see a pair, do it without even thinking about it, but while you're doing that, look for an easy pair.
and...learn more ll algs if you already average sub 25.
i average 32 with 4LLL. (and i know i need to practice my f2l, it takes 27 seconds on average.)