Rejection is almost a given in sales. Even people with bad personal hygiene at pubs see less rejection than salespersons.
Improving your attitude and mentality can help salespeople overcome the problem. It will keep you moving and doing the series of things needed to succeed.
1- It is not personal! The customer rarely hangs up, does not return messages or turns you down in person because of your name or address.
2- Keep trying without worrying. Tenacity will be rewarded.
3- Clients can see or hear a lack of confidence and a defeated attitude. Don’t give the person who rejected you the pleasure. Keep at it.

Sales managers need to dispense confidence. Threatening, setting ultimata or deadlines is counter-productive. Instead, sales managers need to praise the sales team as a group and individually. Pick one quality for each salesperson and make it known to the person. Remind the salesperson why they were hired, which qualifications they have and how you beleive in them. Do it often.