With that out of the way, let's talk fabric protectants. Once you have cleaned fabric and rinsed the fibers, I highly recommend using a fabric guard. Regardless of what brand you use, how you apply it is what determines how effective it is. My personal two favorite products are 303 High Tech Fabric Guard or Duragloss #341 Convertible Fabric Restorer. The process:
1) Clean, rinse, and allow fibers to be protected to fully dry
2) Using a hair dryer or heat gun, heat a small 12'' x 12'' area (roughly) to at least 85 degress F, not much hotter
3) Spray section adequately and allow a few minutes so the fibers soak up protectant, immediately wipe away overspray from other material
4) Using a low setting on hair dryer or heat gun, "bake in" the fabric protectant until area is dry
5) Once all fabric has been cleaned, treated, and "baked in", park vehicle in sun, and allow it to sit overnight to fully cure
6) Repeat application if desired
Please keep in mind that you want to use low settings to avoid melting or damaging fabric or surrounding material. Always wipe overspray from anything other than fabric.