Loosen up at the same rate as your prospect or customer. People look for a company and business with a similar style and personality as them. If your prospect wears a suit, you need to wear a suit. If your customer addresses you as "Mr. West," you need to address her as "Ms. Edwards."

In fact, it is even better to stay one step ahead. If your prospect wears khakis and a button-down, you should wear a light suit. If your customer calls you by your first name, continue to address them as Mr. or Ms. until they ask you to use their first name.

Keeping up your professional appeareance and manners is vital to gaining customers and keeping them.

Avoid bringing up personal matters in a new business relationship. This goes along with the first point. Your prospect is looking for a particular level of professionalism. Let your prospect introduce personal information before volunteering your own.

Many businessmen and businesswomen believe you must get buddy-buddy with a prospect or customer to have a good relationship with them. In reality, prospects and customers are not always looking for friendship--sometimes it is just business.

Wait for personal cues from your client. If you become too informal too fast, they may view you as unprofessional, unrespectful or even untrustworthy.

Bashing competitors is taboo. When competitors are brought up in conversation, the natural reaction is to go on the offense and begin bashing them. Never, ever do this. As far as you know, your prospect is currently working with that competitor and actually hired them personally.

You should believe in your product so much that you don't even view yourself as having competitors. If your competition is brought up in a sales meeting or other such situation, all you need do is list a few ways your product is different from that competitor and, therefore, better.

Bashing your competitor may get your point across, but it will also probably wreck your image and lose your business. Blasting rivals is highly unprofessional.

Be punctual for all appointments. Never leave your client waiting. Not only is lateness unprofessional, it is insulting. Your prospect's or customer's time is no less important than yours. They have meetings to attend, calls to make and letters to write just as you do. To be late to an appointment is to tell a prospect or customer you do not value their time.

Make sure you are on time to every appointment. If the appointment is not at your place of business, it would even do well to be two or three minutes early.

Punctuality is an absolute must for every professional. Show your respect by being on time.