Make sure you have followed the above guidelines and those of the publisher, if you have them.
Don't send more than six samples, or more than can comfortably fit into an A4 envelope. Ensure you have enclosed an appropriately sized SAE, if you wish your work to be returned. Never send originals. Send a covering letter, but keep it brief and concise, anything longer will not be read and may put the publisher off. If you have been published before, it worth mentioning this in your letter. Expect to wait up to six weeks for a reply. Please don't ring the publisher two days after you have sent your masterpiece. Be patient!
It is always advisable to keep copies of everything you have sent out and maintain records of what you have sent to whom, where and when. This will come in handy when you sell an idea that you may have issued to a few publishers at the same time. If it is bought, you must inform the other publishers that that idea is no longer available for consideration.