There are several methods for forming strip footings, but the best method depends on the specific project requirements and site conditions. Here are a few common methods:

1. Excavation Method: This involves digging a trench to the required depth and width of the footing, followed by placing reinforcement and pouring concrete into the trench.

2. Formwork Method: This method involves creating a formwork or mold, made of wood or metal, to the required size and shape of the footing. The reinforcement is placed in the formwork, and concrete is poured into it.

3. Pre-cast Method: This involves casting the footing in a factory or pre-casting yard and then transporting it to the site for installation.

Each method has its advantages and disadvantages, and the best method will depend on factors such as site access, soil conditions, project timeline, and budget. It’s best to consult with a structural engineer or contractor to determine the most suitable method for your specific project.