To start with sales requires a lot of patience.
Preparing for Sales tasks (or job):
Sales is not as tough as some consider. It is actually as easier as making and maintaining friends (or a single GF(for boys) for a life time
In other words it might be as hard as possible or as pleasing and comforting as it can get, but it all depends on how you handle it.
To start with a soft spoken (*or written) language is critical for sales. Always listen, and "never listen to reply", instead "listen to understand" this makes sales that much easier.
General Sales tips:
Always say what they wanna hear (listen) and not what will sell things to you. Start slow and take your time to build trust before starting to speak in a sales voice.
Be friendly to your clients, but never become their inner-circle friend. Never bargain too hard, either back off or let go, this will help you win more often than a long negotiation does.
Finally keep in touch with your clients and potential leads (already contacted unsuccessfully) for you never know when they will be in need of your service again.