A few don’ts…..
Don’t over sell your book – don’t say it will be a bestseller – let the experts judge that.
Don’t sound like a car salesman – keep the proposal professional and to the point.
Don’t do it scrappily and then apologise for the proposal – it should be in the best form you can provide – you only get one chance.
Don’t make mistakes – check and recheck the spelling etc.
Don’t put too much in – remember it is a proposal and not the first draft of your book. Keep it clear and organised.
Don’t use fancy fonts or coloured paper. Publishers are not swayed by gimmicks, they are interested in the readability and marketability of the book.