Tips to my favorite games: Destiny, CounterStrike GO, League Of Legends, and various COD's
DESTINY: Crucible; When playing rumble, always rock the shotgun for the shotgun\melee combo! Hand cannons and auto rifles are the best primaries! When playing control I use snipers and aoe grenades to watch the b flag, aoe means Area of Effect. If playing clash, just rock whatever you feel like using because there is no actual goal besides get kills!
PvE; Shotguns are really of no use in the story, use snipers or fusion rifles! Rockets are recommended for boss fights just because they do more damage at once. One big thing is to make sure that everyone in your fire team has a headset so you can call out when your about to go down or where things are spawning!
CounterStrike GO: Probably my favorite game, the biggest thing is to stand still and crouch when you shoot because the spread of the weapons are ridiculous. One of the biggest debates, M4A4 vs M4A1-S, I recommend the M4A4 just because i feel like the spread is smaller and it fires a little bit slower making it easier to pick people off from distance. When on T side always try to get the bomb down just because it makes it a lot harder for the CT to react and rotate, and make sure your teams setup is good enough to at least delay the CT for about 10-20 seconds! If you are pushing an open bombsite always have smoke or a couple of flashes because open sites are the easiest to cover! CT side players always send 2 A, 2 B, and 1 mid on every map, have the person on mid be ready to call crosses, if they have an awper, and always be ready to flank! That's about all I can say just because I have only been playing for a couple of weeks now!
League of Legends: If you're in ranked play meta champs and don't troll because that stuff is SO annoying. In normals do whatever you want, break the meta play teemo jungle, adc vel'koz and something really op is quinn mid or top so check that out. AP Xin Zhao works, jus the other day i went 13-2 with Lich bane, Rageblade, mejais, sword of the occult, scorcerers boots and a Zhonya's. 19 minutes into game i had 1200 ap on veigar, he is very op. In normals always get stacking items for the fun of it and you never know because it could bring you back once you get going! That's all though.
Call of Duty: All call of duties are really the same, always use the real overpowered guns like the msmc, m8ai, asm1, bal-27, and more. If you are trying to snipe, stop. Snipers are the most annoying things about call of duty, especially if they're on your team because they are literally a walking kill streak...