i could give long answers. But in short :
Try new things.
Take a lot of risks.
Read a lot of books.
Find "you" and be "you'.

Hello, if you have a side job then read entrepreneurial books and watch videos by successful leaders specially your role models.
Apply that in your side job. it would greatly benefit if your job is a people persuading one.
If you dont have a job, then find a job where you deal with a variety of people. eg call center, receptionist, waitressing, sales,etc.
if you dont need a job and can take risks then plunge in. Do a market study in your vicinity and find the right ideas and START.
Call if you want a more customized answer.
Learn from everywhere and anywhere. The most valuable skills are learnt by practical examples only.