Make them food and take it to them. Invite them over for a bbq. I found that the best way to make friend is be friendly. Strike up a conversation and let them do most of the talking. People love when others are interesting in something that interests them and they get to walk about it.

Go ask to borrow something they will have. Everyone likes feeling helpful

Make some baked goods or bread and drop it off. I like to use the excuse of “I accidently made too much, would you like these?”

Invite them over. Have dinner, drinks, hang out, do stuff you like to do with them. Watch sports, or a movie. Listen to music. Grilling is a good outdoor excuse to wave them over.

But keep in mind, proximity doesn’t necessarily make for good friends. You might not enjoy the same hobbies or foods or whatever. You may not enjoy each other’s company. Worse still, you might have different feelings about hanging out than they do. Are they close enough that you’d feel obligated to invited them to everything?

It’s best to invite them over a few times, but maintain boundaries.