Crouching is your biggest friend in sneaking as you make no sound whatsoever when squatting on the floor. If there are enemies anywhere nearby you should be crouched, always, never assume someone won’t hear your clunky footsteps, they probably will.
Patience is a Virtue
Take your time. There is no greater advise for the stealth player. Taking it slow lets you analyse enemy patrols, look for gaps in sight, weigh up options, and more importantly recharge your batteries.
A Stealth player should be making as few takedowns as possible, and as such it’s recommended that you have a personal space policy, vowing to only take out guards who wander a little too close for comfort.
A non lethal takedown is always best, it’s worth lots of XP and is unlimited as long as you’ve the patience to let the battery recharge or have a pocket full of energy sweets.
In a similar way that iron sight aiming is better than aiming from cover, crouch walking without your back from cover is quicker than ealking along a wall, and guaranteed silent.
It’s advisable to use your basic movement between cover as sometimes you don’t know if Jensen will perform a quiet turn or a clunky roll, which can alert unwanted attention. Use cover to scout out your route, but when you want to move do it off the wall.
Deus Ex’s social gameplay is a close relative of the stealth gameplay as it’s often a non lethal way of dealing with situations. That’s not to say it’s easy, the random nature of the conversations certainly makes them difficult to write about.
The most important aspect is to read the responses available and focus on the one that sounds most appropriate. Listen for buzzwords in the enemy’s words and try to match them up with your available responses, one will often stand out if you’re paying attention.
The Cloaking augmentation is one of the most useful upgrades by far. Increase it to the maximum duration at the first possible opportunity, alongside battery recharge, and you'll be able to slink past most encounters with no trouble at all.