Acquiring this achievement is easier than it sounds, as "Give Me Deus Ex" shouldn't be too difficult even for new players, as long as you are cautious and have good coordination. It is best to attempt Foxiest of the Hounds and Pacifist on a Legend playthrough for the recommended stealth tactics.
Stealth and non-lethality are crucial, as the enemy A.I are now more aggressive against intrusions. Maintain a low profile at all times. Keep out of sight of cameras and patrols and remember to hide bodies whenever possible.
Never attempt any hack that you think can cause an alarm, maximize your hacking skill to prevent hacking failures. Most story related hacks are only around level 3-4.
Sneak past enemies as much as possible. If you can, utilize the cloaking aug for better movement inside hostile territory. Do not arouse any alarms/attention to yourself. Try maneuvering large areas behind cover or in vents.
Avoid large firefights (Highland Park, crashed VTOL,...) as the opposition can easily overwhelm you. Reduce combat to a minimum. Should combat initiate, immediately take cover and keep an eye out for flanks.
Ignore side quests or perform only the ones that do not require infiltrating/hacking/killing.
Invest as much Praxis in stealth and hacking as possible. Helpful upgrades such as the Quicksilver Reflex Booster or the Icarus Landing System are highly suggested. The Typhoon Explosive System is handy for ending boss fights quickly, maximize it if needed.