One of the most important things someone in sales or head of your own business can do is to learn to NOT take rejection PERSONALLY. Is it easy to learn how not to take rejection so hard? No, but it is simple.
Go on a "rejection drive" - you know, like a food drive, or toy drive - you are going to intentionally work to hear more "no's" than you normally do.
1. Ask for MORE business and opportunities than you already are doing. Strech out of your comfort zone, knowing that you are working to get a "no" - however, if you DO get a "yes" - accept it! Example: contact someone you normally would think to be more of an expert than yourself - someone more busy and perhaps more financially succesful. Propose something that could be a "win" for both of you - knowing that you're stretching out of your normal zone, so if they say "no" - you can chalk it up to your "rejection campaign". However, if you get a yes, well then, woo hoo! All the better.
2. When someone says, "nope, we are not interested at this time..." ask if you can re-visit the idea or proposal later down the road, or ask them if there is anything that could be changed about it for them to want to participate. Thank them for their time, regardless of the outcome.
3. Eventually a switch will "flip" inside your brain - and you will realize that people say no for many reasons - the timing is not right, they don't have funds available, they don't understand the value, or for several other reasons.
4. If necessary, put the words, "It's not about me" somewhere at your desk.
You are wasting valuable opportunities by drowning in self-doubt and self-pity if you think that you have been rejected. Get over that,and find real reasons then resolve them and win that business.