Founders How to Learn to Sell?

Founders of startups: How do you Sell better? I have sold a little but struggled to make it a process. a. I cannot handle the endless follow ups, b. I tend to not do the essential wining and dining cultivating necessary to chase a big deal (I simply don't have the time or funds given the startup), c. I don't take 10 rejections a day very well - it spoils my day. It annoys and demotivates me that Sales only becomes more as a Founder. But I have to learn. Anyway to make Sales feel better and just BE better? What is your process: after outreach, how do you cultivate a contact? How then do you ask for a Sale?