Go back and pick up Golden Eye on N64 and play for a few years. Then Pick up Halo and play for a few years. Work you way through the Halo franchise and spend at least one year on each (Skip Reach because it was garbage). When you get bored with Halo, throw in some Call of Duty starting with 4 but don't neglect Halo for more than a few days. Now all CoDs are essentially the same so you should be able to knock this portion of your training in a one year for the whole franchise. After, this you should be a crucible stud. FWIW...this seems to be the story for everyone actually good in crucible. I failed at this training plan and am relegated to a lifetime of sucking at all that is PVP. If you can get a .75 K/D, you're doing pretty well in my book.