Generally, it's best to shoot your way through your first time. This way, you'll be able to explore and learn the levels more freely which can help you on future stealth runs, should you choose to attempt it. There are a few ways this can be made considerably easier.
First, as others have said, pick the GEP gun. It is supremely useful, and ammo is not as scarce as you would think. Even after aquiring other tools, the GEP is the best tool for taking out large robots.
Second, on the far side of Liberty Island is a small bunker. On the other side of an electricity field you'll find a laser sight. Attach it to your pistol, and you no longer need to put any points into pistols to kick ass. Note: do not attach a scope to your pistol! A bug will screw up the laser sight.
Lastly, upgrade your rifle to master. While some would say it's pointless if you're good with pistols, which take up far less inventory space, this is not true. The shotgun really helps with those annoying spider bots. At master, you can take out almost any enemy, including commandos, in one shot with a silenced sniper rifle. Also, and perhaps most importantly, the sniper sifle will be able to destroy cameras, turrets, and even some doors in one shot as well, essentially giving you a silenced GEP gun.