How to Wash a Cat
Take a big breath and relax. Your state of mind will influence his.
Start with a clean counter next to the kitchen sink. Put towels on it. Don't have them so close to the sink that the cat could grab it. I generally have the cat facing away from the towels and toward the water faucet. Don't have him facing you. He'll try to grab you and climb up your chest. Get your shampoo opened and handy. Consider which hand will be easier for you to hold the cat and which to wash. Set up your towels and sinks accordingly.
Now, plug the side of the sink you'll be using to bathe the cat. In the other side, start the water. Get it to the temperature you want. Turn the pressure down to a slow flow - on that side.
Put your cat into the empty, plugged up side of the sink, facing the wall. I have bathed a cat with and without a towel in the sink. Your choice. Let him watch the water for a few seconds until both of you relax. With your washing hand, cup your hand, fill it with water and "pet" your cat with it. Start on his back, not his head. Do this several times. Slowly move the faucet over to his side of the sink but not ON him. Continue "petting" him with water. If he's relatively calm, increase the water pressure so the sink is slowly filling. Remember, you're washing with one hand and restraining him gently with the other.
Put some shampoo on him and water-pet and wash him. Have a little PLASTIC cup handy so you can scoop some of the water from his side of the sink and pour it over him (it has soap in it - might as well use it to the max).
Continue washing until you are satisfied that he is clean. GENTLY remove the plug and let the water drain WHILE you are filling that cup with clean water and gently pouring it over him. Scratch and pet him frequently. Talk to him. Rinse him thoroughly.
When you are all done, let him drip a little. You might want to gently squeeze his legs and tail to 'ring' some of the excess water off of him. Then put him on the towels and wrap him up gently but quickly. Use old towels. If he has his claws he might snag them a little.
Drying is the hardest part because he wants to run away. Dry him as best you can and then release him in a warm room. Don't let him outside until he is dry.
I hope this works for you as it has for me.