The best thing to do is to approach them first! If you feel to shy try to casually greet them while you are around friends. If that doesn’t work try to work on not being so shy by doing things you wouldn’t normally do (do small things you don’t have to push yourself!) Also, it’s important to surround yourself with supportive friends because friends that are positive and caring always make you feel comfortable which makes you easier for you to get out of your comfort zone. I hope this helped you somewhat.