Check the workshop, its been made specifically to allow mods.
Some tips i found, always use full cover where possible, when hidden if you plan to attack, put at least 2 members in overwatch and take a shot with a third, dont just reveal yoursefl. the people in overwatch will get chances to hit and your last man can move/fire a specific target once the enemy has moved to cover.
flash bangs are great for disabling mind control and stunning lancers.
always go for the lancers in early game.
leave the sectoids and kill troopers first, they will try and resurrect them giving you a chance to kill the sectoid.
You should try out the Long War mod for Xcom 1 then
beat the game, felt a bit short even though it took me 30 hours and lacking in some places with the weapons/classes compared to Long War Xcom 1, but it's alright I guess, waiting on a long war mod for Xcom 2
I'm using pistol and sword improvement mod and skulljack and emp tweak mod, for some variety, later on in commander I found I never used pistols or swords because they were just BAD. Same thing with bluescreen ammo
Out of curiosity, any old enough here to be Xcom 1 (the OG Xcom) veterans- (1994 game, DOS). My favorite game of all time that I really wish would have a good reboot that takes todays level of computers and lets the original version explode with all the potential it had. Would have been cool to be able to wage campaigns to get countries back that had defected to the aliens, extraction missions, soldier MIA recovery missions etc. The original had such an awesome universe mapped out that just needed the memory, graphics and engines we have now.
I'm tempted to get these reboots to see if they somewhat deliver on this.
I started playing some UFO: Alien Invasion which is pretty much an open source more modern remix of the original Xcom. I like it, but it sticks to the original xcom layout too closely, meaning even though the graphics and such are much better and there are some twists to the aircraft and such, it didn't go the extra mile such as having totally new mission sets.