Most excavation is done with sharp flat skim shovels. The soil is carefully scraped, shaving thin layers at a time. The archaeologist is looking for artifacts and for soil changes. An experienced archaeologist can "feel" the different soil textures in a site, or when they've found an artifact.
All of the soil is screened through 1/4 inch mesh to recover small artifacts.
Careful digging with trowel, paint brush, and wooden pick is often required for feature excavation in order to find and map artifacts in place. The soil that is troweled is also screened.