Last fall I planted around 80 garlic cloves, half in late September (here are the step-by-step instructions) and the rest about a month later. Last week I harvested the whole lot of them. And figured that you might want to have a look.
The rule of thumb is to wait until around two-thirds of the plant has turned brown before harvesting garlic.
You need to dig up the soil around the plant in order to avoid damaging the garlic head.
There will be a lot of roots under the head, and likely a lot of dirt packed into them.
I used a hose to gently clean the roots, then allowed things to completely dry out in the sun for a couple days.
Then I tied together several batches of the dried stalks with twine, six to eight stalks to a batch.
And hung all of them in the garage, where they'll stay for maybe a month like this. After that I'll take them down, cut off the stalks and store the individual garlic heads in some type of mesh bag throughout the winter.
If they last that long.
Which they won't.
But you knew that.