The difficulty of this game is absolutely unacceptable. In fact, I could get 100% completion on Far Cry 3 on max difficulty with fewer deaths through the entire game than the second mission of this game on rookie difficulty all by itself!!! What gives??? Is there a mod or cheats for this game to make it any easier? I cannot play this game if I cannot complete any missions.
I think you need to relax a bit and just learn how the game works. Was thinking the same ( minus cheats ) at first with the difficulty being steep but after one or two missions you will get the hang of it. Before too long you will think this game is too easy, unless you are going for ghost, well then good luck to you. :)
As these guys said, patience and gadgets. Do what I did and use the first Grim mission to train. A few tips: -The drone is great, abuse it to lure enemies around with it's decoy noise. Use it, your own noise, or even an indirect gunshot to make enemies move and have them where you want them. The drone's noise is safer than Sam's, his voice gets recognized easy by suspicious enemies. -If you shoot with a silenced weapon just near an enemy, they won't be alerted, but will freak out and go straight to the position you shot from. Great for long distance luring. -I dunno about keyboard, but with a controller, the A button makes the drone fly faster. -Abuse corners, they're the easiest place to eliminate someone. Except for heavies. -The heavies are annoying, you must attack them from behind, and remember to walk slowly when approaching them, not just fast walk crouched or they'll turn and screw you in the last moment. -Grind a little money if you need to, the first Grim mission is good for this too. Get some suit upgrades and gadgets.
http://goo.gl/Wg6w0 "=[_]=! Bump some other boobs, will ya?!" - p "That sounds so perverted, dude. ._." - M
The gear you start with is crappy. You want to upgrade your gear, buy new weapons, gadgets, suits, and anything else, early on. If you don't the game will slap you for even trying to be a spy. Being a spy is not cheap.
The best place to earn money without any hassle is the first mission from Grimm. Even with the starting gear you could sneak through that thing with no KO's no problem. it just takes time and practice.
At first the game seems to be difficult, it's not, it's just a new take on an old formula and you're adjusting to it. Don't expect to jump into the game like a pro like in the previous games in the series.