Agree with above. It sounds like you can pick winners but are too impulsive with your betting. Start with a bank that will be for beyond the day or week. Bet a % of the bank. This will control your impulse betting. Have a spreadsheet to keep records of starting bank, bets and profit/loss. For example, start with a bank of $100 and bet 2% ($2.00). This will keep you going for quite a while if you are losing. Once you have lost around 18 bets at $2 per bet, you will be betting $1.00 (rounded). However, if you are losing, it will pay to see why. How do you select a bet and why? You won't get 'rich' betting 2% but it will stem the quick loss of the $100 bank. Once you start winning, it is possible, then the returns are higher for the same % risk.
I have followed barryb, curious and mardigras for a while now with their thoughts and advice. I have found that Return On Investment (ROI) is what matters not strike rate. Limit your betting to a few races per day. Look for value. Be prepared to wait. Don't follow the crowd and trust your own judgement. Even when you get it wrong, it is something to learn from and the 2% bank will give you lots of 'plays'. There is a difference between wanting to make a profit and 'social' betting.
If you accept less than value on a runner, you may get lots of winners but the winnings barely, if at all, cover the losses. Don't chase losses, you will lose. Keep emotions out of betting (unless social betting and you don't mind losing, it's just fun).
Keep on asking questions on this site, feedback is important as well.