Apply this scramble:
F2 L' B' F2 R' F2 U2 R F R D B F' R' B F2 D2 B L B2 F' U2 B2 U L
Apply this white cross (excuse any inefficiencies; I don't use CFOP):
x2 L F' L B2 R D2
Now look at the white-red-green F2L pair. The corner is in the front-right slot, and the edge is at UR (up-right position). The sticker pointing up on the edge piece is GREEN, and the color of the center piece that is facing you is BLUE. Because these colors are the same/opposites (blue:green, orange:red, etc), we know the white-red-green F2L pair can be solved with RUL moves, and does not require a rotation. To solve the pair, apply
U R U R2 U2 R
But now look at the white-blue-red F2L pair. It is already made on the top left of the cube. But look at the edge piece. The sticker facing up on the edge piece is RED, while the color of the center piece that is facing you is still BLUE. Therefore, we know we have to rotate the cube, such that the center piece that is facing us is either RED OR ORANGE (so it will be the same/opposite in color from the sticker on the F2L edge piece). To rotate and insert the pair with RUL, we apply:
y' U R' U2 R
Now let's look at both F2L pair edges. On the orange-blue edge piece at UL (up-left position), we see the color facing up to be BLUE, while the color of the center piece that is facing us is ORANGE. This pair therefore requires a rotation. But before we solve it, let's look at the next pair. The orange-green edge piece is at FR (front-right position). In this case, the GREEN sticker is facing TOWARDS US. Uh-oh, that's a problem. We only know how to identify edge orientation if the edge piece is in the U-layer and has a sticker facing UP, but this F2L edge isn't in the U-layer and doesn't have a sticker that is facing UP.
Now, imagine doing an R move. This would put the GREEN sticker on TOP of the cube, right? Now, we can compare the color of the edge sticker facing up (GREEN) with the color of the center that is facing us (ORANGE) to know that they are neither the same color or opposite colors. This pair then also requires a cube rotation to be solved. Apply this:
R U R' [put orange-green edge in U-layer]
y [rotate to fix the orientation of the edges, to be able to solve the F2L with only R, U, and L moves]
L U2 L' U' L U L' [solve orange-green pair]
U L' U' L [make blue-orange pair]
F U F' [orient some LL edges]
L' U2 L [insert the blue-orange pair]
R' U' R U' R' U R U' R' U2 R U [2GLL algorithm to solve cube]
Although some parts of this solve were somewhat advanced, there are a few basic techniques that you should now at least understand:
1) How to identify if an F2L pair can be solved with RUL moves, if the F2L edge piece is in the U-layer.
2) How to identify if an F2L pair can be solved with RUL moves, if the F2L edge piece is in the E-layer (layer between U and D).
3) That it's important to know what you're going to do, before you start doing it.
You don't have to actively use this technique when solving. But, if you are ever stuck on how to solve an F2L pair, you can just look at the sticker colors to determine whether or not you need to rotate the cube to solve it ergonomically. Using this strategy will likely help you reduce the amount of rotations that you do significantly, but in order to take advantage of it, you are going to have to invest a split-second to identify edge-orientation. Once you become proficient however, this "sub-step" will become so intuitive, that you will do it without even consciously thinking, and you will do this "sub-conscious thinking" while you are solving other pairs, such that no time is wasted between F2L pairs.
I'm also going to point out that instead of rotating the cube, you could also use insertion moves that involve F or B moves. F and B moves are effectively like rotating the cube and doing R or L moves, but they are often much faster.
