do what dan o. said. but maybe try to bush hog it right before a rain and put out some P and K. do not put out any N. N will stimulate weed growth and clover can make it's own N.

i've had some halfway decent results with bush hogging clover plots that had alot of grass in it before a rain. the clover seems to recover and grow faster than the grass can.

is it getting alot of sunlight? my clovers do best when they are shaded for half the day (like in shadows of trees). the clover that's in the sun all day doesn't do as well. just my 2 cents, ymmv.