Need help with "Cat Burglar" Achievement!

Like the title says I need help with this one. I've gotten close twice, but I always manage to get too jumpy and get seen by a guard. I need someone who's good at stealth/has good ghost skills o help me with this one. If you're interested message me on steam (same name but it will come up as just "Red)

Thanks so much

Need help with "Cat Burglar" Achievement!