I personally wouldn' t wait until spring. Definitely do the soil test. You' ll probably need lime. Start liming now....use round up to kill off the grass, and if you can, burn the dead grass off. If you have a way to rough up the soil afterward that would help. Sow your seed in early fall(if possible press it in)...and you should have a clover plot this fall, and it will really boom the following spring. A few friends of mine, and myself have had good success with doing it this way.