One thing that I would add is just don't pack up and leave once you have been told no. I always stick around and chat for a while. If they tell me they don't allow anyone to hunt because family hunts it etc. I make sure they know that I bowhunt only. If they tell me about people littering on them or not putting gates up etc. I tell them I understand exactly how they feel and I don't blame them one bit and then I point out that in every group you have good ones and bad ones and the bads one usually spoil it for the rest of us. I then steer the conversation back to small talk and give them a chance to get to know me a little better and get a feel for the type of person that I am. If appropriate I tell them I have a liability release that I have had drawn up by an attorney. If you keep the conversation going, at the very least it may improve your chances if you stop by to ask the next time and sometimes during the conversation they will change their minds. I have started with no and ended up with permission on more than one occaision. As far as sending letter's goes, I think it's a good idea. But, only as a follow up after the initial meeting. Most, of the time I will send a letter thanking them for taking the time to speak with me or thanking them for letting me hunt.