I have been trading extensively and reading this forum for approx 4 months and seem to have some how tripped into become consistently profitable.

Could some kind trader please explain to me when it is important to over-balance the back/lay bets. Eg, at present I am backing with $20 and laying with $22, which corresponds to my sudden profitability. How can I recognise the right times to adjust the stakes in order to enhance my profit? Or is it just a matter of laying a bit more if a certain horse has less chance of winning than favourites?
Thanks in advance
Jon