For the more experienced or adventurous use some discretion.

Lay the fav to pay $110.
You like the 2nd fav so only lay to pay $100.
You think the 3rd fav is unders so lay to pay $105 or even $110.
You don't like the fav, lay to pay $120.
There's a 20/1 shot you think is overs so lay to pay $90 or $95.
etc..... the permutations are endless, but always have the first couple in the market right up there.

The more % you have on your side, the less you risk and the more you win.
Doing this even on a bad day you can't do much damage.