>>33218939 (OP)>make their acquaintance >discover mutual interests and common ground>invite them to perform activities that are of mutual interest>make the effort to keep up with one anotherThis is easier if you're meeting them in an already established setting for participating in an interest, like obviously if you meet them at a Tabletop gaming meet up then inviting them to play tabletop with you is a safe bet. The main differences in making friends when you're older is that it requires more planning and effort as you both have more responsibilities and a more busy schedule usually, but that's just life, you work around those things. You can still invite people to drink with you, except maybe it won't be a rush-week wild night of overconsumption and poor choices, it might just be a relaxed night of shooting pool or sitting around a fire with a couple beers on a weekend night. Have your own hobbies, find others local to you that also participate or are interested in those hobbies, go do them together. Simple, but easy? Not exactly, very doable if you want to though.