Pretty much just the title.
As a very small, but highly frequent example, I’ll invite an acquaintance to get a coffee or beer with me a few times but never have this acquaintance seemingly think of me if I’m not directly asking them to hang.
I can’t really figure out why. Maybe I’m a boring person? Maybe I’m abrasive? Maybe most people like to stay in a perpetual state of acquaintance-ness?
How do you fix something like this if you can’t diagnose what’s wrong?
Learning how to be emotionally vulnerable is key to actually connecting with people. The book "Models" by Mark Manson is a pretty good primer on the importance of emotional vulnerability to connect with people. It is sort-of a dating advice book, but I've found it helpful for making regular friendships and connecting with my own family as well.
Another thing that is helpful is learning how to communicate assertively- which is the opposite of being emotionally manipulative. The book "When I say no I feel guilty" is particularly good introduction to assertive communication. A lot of people only learned emotionally manipulative communication, and will be avoided by almost anyone that sees that for what it is.
Counter-intuitively, not being desperate is critical. Be willing to judge if someone is worth your time, and be willing to disagree with people or say no, without letting the fear of being rejected control you. The same authenticity and vulnerability that will make people really connect with you, will also drive some people away, and that is totally fine. The goal is not to be friends with everyone, but to make good friends with people you are compatible with.
Therapy can often be helpful for developing all 3 of the above skills.
Lastly, take the initiative to make things happen. Invite someone to do activities several times before expecting them to reciprocate. People tend to be busy, shy, stressed, etc. - just because people don't reach out doesn't mean they don't like you.