All good positive advice !

A couple or three tips that could work for you.

Like anything else you want to do well, prepare.

I realise this is going to open another debate up but here goes.Throw away the laptops, lever arch files and assorted paperwork and try and learn the songs,reading a song fom a piece of paper means you do not know it.I equate learning a song to learning how to drive a car, when you pass your test you are only starting to learn to drive.learning the words to a song is only the beginning to learning and understanding the song.Get this right and hopefully it will increase your confidence which should lead you to project better.

The voice is like any other part of your body, before use it needs warming up.So before you start, try a warming up exercise of humming a song to yourself, dont laugh but I use "Somewere over the rainbow" or the "White cliffs of Dover"

Try not to be the first person to start, joining in with a couple of chorus songs should get you well warmed up.

As has been suggested find a key that suits you,if you know the key the song is in ask some kind person in the group with a guitar or other instrument to give you it.Failing that carry a pitch pipe,good investment at a coupla bob.

Posture is vital, if you are slumped in a chair looking at the ground you will only project to the the floor. I realise that a lot of people lack the confidence to stand up and sing, so try sitting up straight and hold your head up, not back. Above all practice breathing using your diaphragm.

If you do stand up use the room, project your voice over the heads of the company at a corner . This can act as your personal sounding board.

Again posture, stand up straight, feet slighly apart untill you feel balanced and comfortable, head up and away you go!

And practice, practice, practice............................!