From my days of cold-call selling, and this goes with any sort of selling. Ultimately the customer is buying you and the product second. That being said make sure you have plenty of rest, if a customer can sense duress or any sort of fatigue that means they are not seeing the cheerful and light-hearted personality that makes you such a wonderful person to deal with.
Make sure your clothes are presentable, you want to be professional in every avenue. The business I had was a commercial cleaning business. I did not have any sort of professional shirts or polos so when I went to talk to current clients or went prospecting for new I wore a suit. I did this because even though I might just have been a toilet scrubber, I was a business owner and no one will take you seriously if you show up looking other then the part. There is the argument that you might look too stuffy and not relaxed, especially for some clients if you go that far. I totally get that as I went to rural areas as well, when that happened I switched gears, wore a nice dress shirt, nice pair of jeans and a nice pair of dress shoes that matched my belt. I still looked very clean and professional with the "edge" smoothed out a little.
Always hand out extra business cards to the prospects. Depending on your feeling will determine a good amount but I would say never less then 3 or 4. This goes hand-in-hand with my next comment, always at the end of your presentation ask if they know anyone that might be interested in your services. Business owners know other business owners and usually carry personal relations with one another. If they do not want to give you their info, they have extra business cards to give to them when you show them how well you do and they are excited and want to tell everyone the invaluable contractor they found.
When speaking to the prospects, speak clearly, speak in language they can understand. Do not use isms or "detailer terms" walk up to someone on the street and ask them if they know what the 2-bucket method is. Bet most people are going to give you a confused look. If you are explaining your washing process you might instead want to say... " I even take extra precaution when washing your car to ensure no dirt is transfered from the wash bucket to the paint that might harm it in some way". You do not have to say exactly that, but I think you get my point. The more "industry terms" you use, the quicker you will loose interest in the person because you will confuse them. Remember the term "KISS" Keep It Simple Stupid!
Smile, always smile and be aware of your surroundings. When introducing yourself you want to start off with a little small talk. If you are in their office or just around their facility, find something of interest and start talking about that to break the ice and to put them in a more relaxed stage. Usually photographs on desks or little trinkets on a desk are perfect as these are near and dear things to the prospect. Do this only for about 2 or 3 min, any longer and they are going to feel like you are wasting their time. Time is money for you AND them so be thoughtful and mindful of their time as well.
Shake hands with the person, I do not care if its against what you like to do. If you do not shake someone's hand that can turn a lot of people off. Shaking someone's hand might just be the same to them as sealing the deal or signing a contract, keep that in mind. Make sure it is a firm handshake too, no flimsy, weak crap. A good strong handshake will exude and give an impression of confidence, it will show the client you are willing, able and ready to make all those promises you just made come true.
Well, thats a few things I can think of at the top of my head. I exploited a lot of ideas so that you could get the angle I was getting at. There are several more points out there that others can pitch in on. Just be yourself, know your product, know what way you want to position your product, sell it with a smile, sell it with personality, sell it with integrity and you will do great!
Good luck!