Be somewhere where people congregate repeatedly. Regular at a pub, bouldering gym, arts meetup. Really anything where you'll see the same people consistently.

My rule of thumb that it takes something like 3 reasonable length conversations with someone in a short timespan (weeks to a couple months, short enough that you remember the person and their associated context each time) before you really exist to each other.

So ask yourself, what interests do I have that will facilitate this repeat interaction? Then you are left with the work of figuring out what groups and events exist, and actually going to them consistently.