To me, the theory of targeted practice doesn't really make much sense in cubing, especially for an idea as abstract as "look ahead". It makes a bit more sense with algorithms, but maybe you can show me a video about look ahead that gives specific targeted practice techniques, because every video I see on look ahead just kind of explains the idea of it and why it's important, but doesn't really explain how to get better at it.
I know nothing about Roux, but for CFOP many people recommend blind practice for improving look ahead. The point of look ahead is that you are looking for what you are going to do next rather than looking at the pieces you are currently solving. That's not going to be easy if you can't solve pieces without looking at them! So a good exercise to start with is to find the corner and edge of an F2L pair, close your eyes, and connect-and-insert them without looking.
That one is pretty easy. The next step is to solve them blind while focusing on something else. Try this: find the pieces for two F2L pairs, then close your eyes, and insert one pair while mentally tracking how the other two pieces move. It's surprisingly difficult! Even with eyes shut, the brain wants to mentally watch the pieces being solved. When I first tried doing this, I lost the ability to even insert the pair, let alone follow the other pieces. But after a lot of practice it got easier, and I noticed that in my solves (with eyes open

) it also became a lot easier to take my eyes off the pieces I'm solving and look around the cube more.
I did see the video where Feliks says full solves are the best practice, but I've also read somewhere that he can solve two F2L pairs blind - so the exercise above, plus insert the second pair.
Another method that gets recommended a lot is to solve to a metronome beat, but I don't like that, because it tries to enforce no pauses without really helping develop the skills to avoid them.
Targeted practice isn't essential, but it can be beneficial, and it can be fun.