Yeah splinter cell is one player only.
AS for Ghost Recon, I know about it, but I haven't played it. It's similar to most tactical first person shooters. I played alot of Joint Ops and I know that enemies can be really hard to see, especially in a lush forest environment game like Joint Ops, you have snipers armed with .50, prone, or crouched behind a plant or a tree. On top of that, they are dressed in ghillie suits. The best thing to do is keep practicing, notice the surroundings and look for inconsistancies in the graphics. If you see a shady patch that looks not natural or a barrel of a gun sticking out of a bush, then you know where to fire.
This part is for everyone in general for who have played these kind of games..
AS I stated earlier, I'm not quite familiar with Ghost recon. But I can give you some pointers. For cover, never take a trail on the roads or a clear patch of land, avoid running up hills in a straight line on the horizion where everyone can see you. Use your cover, swerve through the forest, when moving in unoccupied territory take the low hilly ground for cover then move to a higher spot. Avoid running in a straight line, better yet, avoid running at all, if the game has a crouch movement, use it, not only will you be harder to spot because your moving slower and your closer to the ground, you'll improve your shot accuracy as well. If the game has a prone option, then find a spot at a choke hold and stay there, and fire. But move constantly from the same spot. Human opponents will remember where you once killed them and they will be back for ya.
What weapon are you using in Ghost Recon? For starters if it has the option I would suggest playing the role of a combat support sniper, stay behind the big guns, pick off the sentries and the enemies who are standing still when firing. Then, as you learn, pick up the assault rifles, one's with better aim and accuracy. I wouldn't advise starting with a light machine gun, those things take a great deal of practice to fully get to understand how their recoil works. With any assault weapon, never hold down the trigger to the point where you have to reload your ammo, take short controlled bursts and when the enemy is down and you have about 3 shots left then change your magazine because your not going to be wasting valuable seconds while changing it in the next firefight.
Second, if Ghost Recon has a binocular or scope funtion in the game, then use it as much as possible during cool downs. I'd say 80% of the time in a online game you're never killed from the front, but from a rear or flank attack. Always be on the look out, know your surroundings, find cover in a thicket of trees. Use your binoculars or scope, then move about 30 yards, do it again for a full recon of your occupied territory. If you have zoom on the scope or binoculars, well then, more power to ya.
Groups do have their advantages, staying in a smart group spread out in smart locations is one of the best things you can do to supress, and gain controll a firefight. But online, the right team is hard to find. You usually have jokers who will fire off rounds of munition in the air or at no real target just for the fun of it. Not only does this give away your location and draw attention to the enemy. But also if your traveling with such individuals closely you have a greater chance of an opponent popping up of of the grass with a M249SAW and mow both of you down.
If Ghost Recon has night vision and if it has a setting to adjust the brightness, keep it in a 50-60% luminosity, you don't need the retinal barrage of a max frequency. this is great too for urban areas where there's lighting all over the place so you don't see a splurge of massive bright white.