Show you're serious. Offer to make a large earnest-money deposit and as large a downpayment as you can. Putting more money on the table up-front shows the seller you're serious about the transaction and willing to put your money behind your intentions. Attach a copy of your mortgage preapproval letter to your purchase offer. A prequalification letter is helpful, but a full approval, subject only to an appraisal of the property, is even better.
Sellers favor buyers who demonstrate that they're financially able to close the transaction.
Agents advise getting your preapproval letter from a local mortgage broker or lender who has a good reputation among the local agents. Work with a real estate agent who is successful and well-known to other agents. Also, if your agent will be faxing your offer instead of presenting it in person to the seller, a cover letter should be attached. The letter should be addressed to the sellers and should outline the strengths of your offer. Don't add unusual or unnecessary contingencies or requests to your offer.