I can talk to my family and friends just great. Problem comes to dealing with strangers in relation to business.
I will practice to myself what I want to say but when the time comes to approach them, I end up saying something totally different and stupid and end up not getting what I was hoping for. I find it easier to write letters or email to these people because I can say what's exactly on my mind and not be afraid, but I can't use those options all the time.

Advice anyone?

Sounds like social anxiety and there's plenty of tips for it a Google away. Just take a deep breath and relax. Will yourself to breathe and relax. Structured techniques such as meditation may also help. I like to imagine the other person drunk, on their knees, and puking into the toilet. ;) They are not so intimidating then which helps the mind focus less on monitoring the mechanics of the interaction and analyzing the other person's responses and more on listening and constructing your end of the conversation.

Any way you can find out about these folks in advance? If not then, when meeting face to face for the first time take a minute to relax around them, such as ask them a personal question, or pay a compliment, anything to interact as a person, and see them as another person, just like you.

Practice, speaking clubs, or just practice things, go buy something at walmart, go back the next day to get a refund, do it without a receipt where it is harder the next week.

Take some sales classes in dealing with people.