I tried it. I was shit at it. I Gave up.
The best results I had was backing the favourite and then laying when a race turned in play for a couple of clicks below for a small profit as the race progressed, with a stop loss above that for a tiny loss in case the market turned the other way. The tiny losses pretty much cancelled out the tiny profits and it just seemed like it was a bit beyond me and I was wasting my time.
I never paid out for any course but did invest in a years subscription to Bet Trader. Which I don't entirely regret as its a useful tool and has been a Godsend for matched betting on the greyhounds.