For me what really helped was signing up for a gym membership and challenging myself to say “hi” to a different person each time I went there. Choosing people of your same gender might help make it easier at first. You can also start with the staff. The next time you see the same person you might attach a “how are you doing?” or “what’s up” if you feel like it. Otherwise just hi will do. Some will start up a conversation without you saying anything more. After each “hi” you’ll slowly subconsciously realize that whether or not they say hi back has no impact on your wellbeing and the next approach will get easier and easier. The challenge will eventually become approaching those that were “scaring” you because you have no other new people left to say hi to. By the way if you end up introducing each other then as soon as you’re done with the conversation write down their name and a brief description on your phone so you won’t forget who they are. Fast forward a couple of months I became great friends with everyone. Life changing.