At 25 seconds with around 20 of those on cross and F2L, that's exactly where your time is, so you're looking in the right place. A few things that helped me most at that stage:
Cross: try to use the full 15 seconds of inspection to plan the whole cross, not just the first two pieces. If you can't plan all four yet, plan three and track where the fourth goes while you solve. A few cross-only solves each session (scramble, plan, then solve the cross without looking) builds this up fast.
F2L: slow solves are the big one — turn at about half your normal speed and force yourself to find the next pair while you're still finishing the current one. The pauses between pairs are usually where the seconds hide. Once you can get through a whole solve without stopping, speed back up a little at a time.
A simple routine that worked for me: 10 minutes of cross-only practice, 10 minutes of slow, no-pause F2L solves, then a few timed solves to finish. Stick with that most days and the cross+F2L chunk comes down pretty quickly — getting it from 20 seconds toward 12-13 is very doable from where you are now.
