A few do's and don't's, based on my own preferences and hang-ups:

Learn your songs. If you can't learn long ones, sing short ones until you get more confident.

If you can bear it (I, like most people, find this difficult), record yourself singing and listen to it critically.

If you accompany yourself, be aware that the song comes first, and the accompaniment should fit around it, not vice versa. Practice without the accompaniment until it sounds right, then add the instrument.

And whether you sing accompanied or unaccompanied, choose a comfortable key for your voice, and work out a way of finding that key (or the starting note, if you don't want to get technical) when you get up to sing. Get a pitch pipe - or just say, "Can someone give me a D (or chord of G)?" and they will.

Don't apologise before you've even started. I have a personal thing about this - so many singers begin by saying, "I don't know if I can remember the words to this one.." or "My voice isn't up to much tonight," or "I don't know if I'll get the right key.." These are your own problems and it's not right to inflict them on the audience. Sort them out for yourself. Everyone makes mistakes and gets things wrong, but good singers and professionals don't draw attention to possible problems before starting, there's no point.

Don't sing too slowly. It's harder work for your voice, and can make the song drag for the listeners.

Try to convey some enthusiasm for the song, both in the way you introduce it and in the way you sing it. Sing the song so that it matters. The tune matters, the words matter. Show that you care about the song and your audience will warm to the song and to you.

I'm sure you know a lot of this, but you did ask...

Marje