As a long time player who has been in the higher end of the skill gap. Reviewing games is by far the best advice you can give to that player who wants to get better. Halo 3 for me is what REALLY sparked improvement on my play and theater is what I would credit directly for that. Now that being said, there are some VERY few players who can review and adapt "in real time" to address bad habits they form but generally they have unnatural levels of discipline. If you want to make natural and fun progress through review, try making a montage (I prefer a blooper montage for this job). You'll likely find some fun in this and you WILL see your bad play while hunting for clips.