For F2L, I learned it intuitively. There are some cases you can look up to find better solutions for the problem but it is best to learn F2L just by doing it rather than Algorithms. I started off at 2 minute average with beginners method. When I learned the basics for F2L, my time went up to about 2 minutes and 45 seconds then gradually got faster. Took me about 1 month to Learn most of the PLL Algorithms and about 7 OLL Algorithms just to solve final layer and to become comfortable with F2L enough to get sub 1 minute. After that, I just figured out tricks and shortcuts to make things solve faster.
For Learning OLL/PLL and getting fast at it, it just takes alot of practice and then it becomes a natural movement when executing the movements.
For F2L, just takes practice finding the pieces you need to pair up and to put them in the correct spot.
You will find yourself practicing F2L and building the cross more than actually practicing OLL and PLL because F2L and Cross building are really the only two things that are hard about the method.