Head to one end of your field with a scythe in hand. Put on a pair of sunglasses or protective lenses to keep wood chips out of your eyes.
Swing the scythe from side to side at just above ground level. The scythe will clear most small bushes and trees without much fuss.
Walk in a straight line along your field's border from the bottom to the top of the property. When you reach the top, turn around.
Walk back down the property, clearing the brush and plants as you go. Continue to make uniform lines up and down the lot until the entire field is clear.
Rent or borrow a tractor with a shredder or brush attachment and drive it up and down the field to clear any large objects your scythe could not handle. A shredder will also shred the toppled brush, removing the need to burn or haul it.