Step 1: join a CAMS affiliated motor club (any rally club will do, as they DO run tarmac events)
Step 2: Get a CAMS Level 2 licence
Step 3: Scan the events calendar the club gives you. Look for supersprints or hillclimbs. They are both held on tarmac, and a good way to get started
Step 4: Buy a helmet
Step 5: Go racing.
This is obviously very simplistic, but it will get you started into competive tarmac racing, where you can run your street car. there are often track days held at the tracks - many of the car clubs run them (WRX club, Honda club to name a couple). On these days, you can take your car out for a lay, and they sometimes arrange professional tuition.
Once you start "hanging around the scene", you will quickly meet lots of like minded people, who can steer you in the right direction, depending on what you want to do. It's easy to then learn everytihing you need to know about motorsports.The supersprints are good, as you usually get a range of cars, from nearly stock family cars to full on open wheelers and sports sedans.
Just Do it!! (it doesn't have to be expensive).
Oh and as far as being picked up for a professional drive - there's a lot more to it than having talent. Club level motorsport is chock full of talented drivers who never made it to the top, because they:
a) didn't have the funds
B) weren't in the right place at the right time
c) Didn't present themselves well
d) didn't get the opportunity to learn to race properly
e) name any reason you want.