I send the standard request and then when someone accepts I send a longer message along the lines of "what are you up to these days?".
A useful tip I heard was that if you have been out of the workplace for a while, remember that your connections or potential connections will remember the pre-kids/professional "you" so you can take a lot of confidence in that!
Also, a very useful feature is the one that lets you see who's been looking at your profile. I will usually try to connect with those people if I know them.
I usually just send the standard message, as I expect people are used to it by now, like a fb friend request.
I connect with people who are friends as well as professional connections, as they might have a useful connection further down the line. So don't worry about whether it's ok to connect, just go for it! The worst that can happen is that they don't respond!
Just sorting myself out on linked in. Scary place. What is the etiquette regarding requesting connections? Should I just send the automated connection request or do you write a personal message to everyone you connect to e.g. my previous boss (a technophobe who has two connections) his boss (who I met only a couple of times) university tutor etc