Sending that first message is the part most people get stuck on. You're writing to someone you've never met, you have no idea how they'll take it, and there's no tone of voice to help you out. The good news is that a first message doesn't have to be clever. It has to be short, warm, and clearly meant for that one person rather than for anybody at all. Here are five things that make the difference.
"Hi, how are you?" gets deleted, because it could have gone to anyone. Read the profile and pick one thing to respond to: a photo taken somewhere you recognize, a hobby they mention, a book on their list. Something like "I see you've taken up watercolors. How's that going? I tried pottery last fall and every mug came out crooked." That message could only have been written to that one person, and that's what earns a reply.
Three or four sentences is plenty. A long first message is a lot to answer, and it spends everything you might have talked about later. Say hello, mention the thing you noticed, ask one question, sign off with your name. There's no prize for filling the box.
A message made up entirely of questions reads like an interview. Offer a line about yourself so they have something to pick up on. One sentence does it: what you got up to over the weekend, why their photo of the lake caught your eye, what you're halfway through reading. You know yourself well by this stage of life, which makes this a lot easier than it was at twenty five.
A little humor works well, and a light touch is best in writing, where there's no tone of voice to carry it. Gentle, and slightly at your own expense, is the safest ground. Steer clear of jokes about their looks, sarcasm that could land wrong, and anything off color in a first message. If you're not sure how a line will read to a stranger, leave it out.
Finish with one open question they can reply to without much effort. "What kind of hiking do you do?" works far better than "Tell me about yourself," which is a big ask of someone who doesn't know you. One question, not five. You're starting a conversation, not handing them a form.
A few last things worth doing. Read it back before you send, because typos are easy to make on a phone. Use their name if they've given one. And don't send the same message to twenty people, because it shows. If you don't hear back, that's normal and it's rarely anything to do with you. Move on to the next one, and keep it just as personal.