To till or not to till
It's always preferable to limit soil disturbance (ex: tilling) because it will bring weed seeds to the surface, may encourage soil erosion, and can damage soil structure if done frequently and/or when the soil is too wet or too dry.
Rake the soil if there are few weeds and the soil is high in organic matter and friable (it easily breaks apart into small clumps and crumbs). Tilling is ok prior to planting especially if you are incorporating organic matter or there are many weeds.
Don't till when the soil is wet. It's ok to till when a handful of soil breaks apart when bounced up and down with your hand. If the soil stays together, it's too wet.