Here's a tip: don't move slow. If you must move slower, then crouch. It will muffle your sounds. When around areas where you suspect enemy presence, crouch to move into position. Coordinate movements with your team. Then when you execute, move fast.
The reason why I'm saying moving slow is useless is because it makes you an easy target. When someone has the drop on you, depending on the angle, there is a chance they can miss a few shots if you're moving faster, which gives you a higher chance of survival. Moving slow gives them the ultimate advantage and will make you an instant elimination.