People think it's a bad thing when weeds are taking over your garden. The big advantage is all those free greens. There is another benefit - observing the weeds that are there and the condition that they are in is a good indication of the health of your soil. If you have lamb's quarters and stinging nettles, you should be happy - your soil is high in nutrients. If you have lush weeds of any kind, your soil must be pretty good. If your weeds are yellowy, stunted, twisted - you need soil amendment of some sort.
Treat your soil like a forest floor, add coarse organic material, woody debris and duff. Don't rototill, it breaks the beautiful network of mycorrhizae that protect roots. Turn by hand if you have a small area. If you must rototill, try not to pulverize the soil. Run over it quickly, retain the lumps.