Also, if you're really having trouble you could sign up to AbsoluteWrite.com and go on Query Letter Hell, where people crit each other's queries/cover letters - you can post your own once you've made 50 posts on the site as a whole. But tbh I think it might be a sledgehammer to crack a nut in this case - AW is mainly American and the query letter has to work much harder there because the norm is to submit the initial query before the chapters.
Hi Bssh, I have just completed my first children's book and having survived three rejections I am now into the second round of sending off. I found the covering letter a little tricky as there was so much conflicting advice out there. I was concerned that my covering letter was not up to the job and may have put agents off reading my ms ( at least this is what I am telling myself- easier to blame this than a ms that is complete drivel) but I found the following advice and examples from (from Gemma and Molly at The Bent Agency) an absolute godsend.
Hello. I'm completing my first novel and thinking about pitching it to agents. Are there any websites that feature real life cover letters to agents or editors. I know I need to keep it punchy and short and am looking at book blurbs for inspiration. Additionally, do any published authors here care to share a few of their cover letters (when they were first pitching themselves). Thanks.