Stealth is not just about sneaking past guards, it's about being one with the shadows.
Learn to be a master of disguise. Change your hair color to match the surroundings, wear a trenchcoat to blend in, and for goodness' sake, wear a watch that matches the time of day.
Practice your skills by spoofing in real-time.
Take your spoofing skills to the next level. Learn to mimic the mannerisms of your mark, from the way they walk to the way they talk.
But don't just stop at mimicry, learn to create an entire fake identity. A fake backstory, fake friends, fake family... the whole shebang.
Start by practicing advanced spoofing.