Trading Help

[littlebri]

Hi,

This is probably an easy question to answer, but i tend to understand things better when they have been explained to me,

I was wondering if someone could explain how to manually work how to trade out in small amounts rather than the full amount for level profit.
An example would be, say i'm trading the under 2.5 market, and my initial back bet is £20 @ 1.8 the odds then move down to 1.4 and i place a stake of £25.71 for level profit of £5.71.
What i would like to know is how to manually work out how to lay or back off in small amounts as th price hopefully moves in my direction, so that by the time it reaches my predicted price it is still in a level profit, even though this will bring less profit but hopefully less risk..

Any explanations much appreciated.
Bri