Join clubs of activities you enjoy. Talk to the people at your job. Write a message to your old classmates or friends. Meet your neighbours.
After many, many years of avoiding most of my neighbors I have spent the last year forcing myself to befriend and actually get to know the people around me (we moved here a year ago so new scenery new outlook I guess). One neighbor sucks butt, three neighbors are awesome, another neighbor is weird (like, weird for me), the new family is great but with something Mormon-y about them.
It's really nice. I like these people and I'm glad they're around my family.