Depending on the usage, sometimes allowing a patina to form on a carbon blade is the best way to protect if the usage means it will see extensive food prep where a silicone or petrol coating is not really practical or safe.
Cleaning with water is a good thing as you want to get things like acids or salts or debris off the blade that can accelerate corrosion. However, it is critical the blade be dried off after and not left in water. In some cases, air-drying is also not advised depending how rust-prone the blade us. Some people may prefer an ammonia cleaner or a specialized cleaner for cleaning, but I personally generally use mild soap, hot water, and a soft toothbrush. For severe gumming, I use alcohol. Definitely test any cleaner or treatment on a small area before usage. Some polishes or protectants can alter finishes of metal, wood, plastic, and other materials.
Something like TuffGlid or Eezox are great at stopping rust. I use a lot of Eezox. These are fantastic for storage of anything metal. However, the amount of actual lubrication these products give is less than something such as a high-slip grease. For my folders, I like to use a fluropolymer grease in most cases because it makes the knife smoother and lasts much longer than a liquid lube (this requires you have the right hex/torx/wrenches to safety take the knife apart and put it back together). I also like using VC3 on threads to prevent screws from backing out and protecting the inside of screws/connectors/standoffs/pivots/spacers from internal corrosion.
I also keep a silicone block, scratch pen, and metal polish for touching up satin, brushed, stonewashed, and polished finishes when damaged, and beeswax for wooden handles, inlays, and other wood products to protect them.
You will surely want to get basic tools if you do not have them. Even with adjust pivots or swapping pocket clips or tightening bolsters, if you aren't using the exact size tool that part needs, it's easy to damage cosmetically and strip screws.
And blue painter's tape. I use this when sharpening, polishing, etc. on parts I do not want to damage the finish on. Some shop towels, polishing towels, a microfiber cloth, wooden cotton swaps, and a wadding compound like Never Dull also is a plus to have!
