I joined an online dating site in an interesting way. A guy friend of mine had joined Plenty of Fish (POF) and met a woman through the site. He had a theory about something and wanted to test it. It had something to do with the age and number of contacts. I signed up and found it rather interesting. I participated in the forums and through them, met a group of people who were mostly from other cities. They met weekly for wings and had dinners together on some of the holidays. The local POF often had social events that were organized by members and posted on the forums. I met my current partner at a card tournament that was organized by two people from the group and at a subsequent event (rock climbing) that I organized. He got in touch to ask about family friendly vacations and mentioned having gone to a learn to golf event. We started golfing together and then going to dinner, movies, the ballets, etc. We were friends for the first 6 months or so and then started dating. That was about 6 years ago.
My guy friend's relationship didn't work out but he met a great woman a year or so later and they have been married for two years now. She has also become one of my closest friends. We are all in our late 40s and early 50s.
Having said all that, I think common interests is very important to a relationship so if you can get out and do things you love, you are likely to meet people who like doing the same things and with whom you have common interests. Perhaps join a golf league or take a class but get out and meet people - both men and women. The bigger your group, the more likely you are to meet someone compatible.