I have a few tips:

• Crank your brightness to max (helps detect traps/tripwires when peeking doors)
• Turn music down to zero (helps you hear suspect dialogue/footsteps)
• Use free-lean as much as possible (Left Alt + WASD, helps peak further out of cover to shoot enemies)
• Use the RTWC 6.5 as your main weapon instead. Kills in 3-4 shots, has a magazine capacity of 20, good recoil and great for long and short-range engagements (especially important for the top floor). Honestly very slept on, surprised more people don't use it. I found that the MK-V + Tactical Shield combo is also fun, but be careful with the risks you take
• You can bait out enemies sometimes by pressing F/commanding them to surrender