I have have planted Whitetail Institute Imperial Whitetail Clover in several small food plots for the last 5 years with great success in attracting Deer, turkeys, rabbits, and of course groundhogs.
The prime problem that I and others have had is with weeds and grass choking out the clover. I recommend that you delay planting the clover until mid August and spend the spring and summer getting the existing plot ready by doing soil samples and multiple tillings or chemical weed control so that when your plot geminates, it will come on strong without the weed problem. The late summer early fall is the best time to plant clover as the weeds are about done growing and the clover will be just starting. This will give the clover a chance to spread and overtake the existing vegatation.
Each time you till, you will expose new weed seeds to growth within about a month after tilling. Till again after killing with Round-up and keep doing it until your soil is virtually free of weeds and grass. Even so you will still have weeds and grass grow in the spring and then you will have to treat each with chemicals that selectively kill gass and then weeds without harm to the clover. This has to be done when the grass and weeds are less that 4 " high.
Clover planted in the late summer will feed deer and be an attractant during the fall hunting season.
If you don't have your tractor by spring, use a 4 wheeler and a small disc to do the tilling.
Remember, soil preparation is of the utmost importance. It will be much better to delay planting clover until the conditions are just right. My first clover plot was planted in less than ideal soil conditions and it was a struggle to keep it going 3 yrs. with the weeds.
I have since purchased a tractor and a tiller and for the first time, I will have the capability of preparing the soil as good as 3RRL's plot.
Overseeding works where you have already prepared the soil and the soil is free of vegatation. It also works to fill in spots that could use help in an already existing plot of clover.
I also planted some turnips in the late summer mixed in with the clover and the deer loved them late into the season. Turnips are really cheap, but be carefull to broadcast them very sparingly as the will grow up too close together and not amount to much.
You may also consider planting annuals for the first few years until you have the ground fully under control. I expect that a clover plot that is free of weeds and grass would easily last for 5 yrs. without doing much other than maybe a 6" mowing and annual fertilizer.
Hope this helps. We killed 28 deer on my 75 acres this year! Do the food plots work? You bet they do. They are worth every cent and drop of sweat that they cost.