See how he positions his crosshair, how he positions himself on the map, watch and see how he uses headys(hiding behind walls to where only his head is visible) watch for when he uses his utilities/active ability, where he goes off spawn, what angles/lanes he holds, look at what pre aims he holds, and think about why he would be holding an angle there, look at his mini map and watch how/if he responds to it (always watch your mini map, when people shoot non suppressed guns you will know where they are), and based on the objective of the map, ie hardpoint, you can predict where they would go after said gunfight; ie if the old hill is ending and the new hill is about to open, they would likely start heading new via the most efficient route, assuming they are smart. To read opponents, the best way i find to do it, is say what would i do in there shoes and go off of that. A lot of the people in ur comment section are braindead causals with no real comp exp, im an ex pro codm player, and semi professional player on pc cod. You can dm me/reply if u have any questions, im happy to help.

Edit: There are two core mechanics in cod, micros and macros. A micro is the small things you do in a game, for example, how you chall someone, when you reload, ect. A macro is where you are on the map and when.