I think the best advice is to keep it simple. When you analyse the role of an MC it is to introduce the act to the audience and in most cases keep the evening running to time. I always try not to sound contrived, yes you need to do some research but simply reading the biog out from the programme is not an introduction. Try and talk to the guest/performer before the concert, intoduce yourself to them and ask them if there's anything they would like the audience to hear then be natural and let it flow. If you are on a big stage get to know your stage crew and sound engineer be guided by them.