I think this is good advice for making acquaintances, which is definitely a start.
But, IMHO, turning these acquaintances into friends takes something else: showing vulnerability and being able to support the other person when they are vulnerable.
The comments here have some great advice, but I haven’t seen anyone mention this. Personally I think this is absolutely paramount.
The best friendships I have are with people who I have shared myself with, have been willing to listen, and who have listened with kindness and understanding. People who appreciate that I am showing faith in our friendship by opening up.
Some people will not give me that space. They will look uncomfortable or make awkward jokes. They will always be acquaintances to me, never friends.
Conversely, I must be willing to do this for other people. To listen with understanding, to ask questions, and to know when my opinion is not needed.
Now, for those who want it, here’s my strong opinion: if people won’t do this for you, if they respond by looking awkward or making uncomfortable jokes, then f*k em. You don’t need that in your life, and you’ll find much better people.