Step 1: Recognize the child needs a bath.
This is also called "try to get out of giving the child a bath." This may sound pretty obvious and straight forward, but it's not. It's deceptively complex, because it involves your spouse. If you're a single parent, you probably never have to worry about bathing your child. Good for you.
The key is to get the other parent to recognize the need for a bath without you. This usually occurs by way of a poopy diaper blowout, excessive spit-up or projectile vomit, or playing with dirt, all while you're not home. If you find yourself a part of any of the following phrases, you've past step one and signed up for bath duty:
- "Honey, is this Tuesday?"
- "Did we give [insert child's name here] a bath last night?"
- "Daddy's little girl needs a bath, doesn't she?!"
Step 2: Prepare the Bath
We've reached the point in my house where step two now requires a full-fledged bath tub. I am fortunate in that I am able to dedicate an entire bathroom to bathing the child. If it's in the budget, I recommend it. I also recommend getting the other parent to prepare the child while you prepare the bath. Plug the tub, add warm water, and make sure you have a clean wash cloth and towel. Under no circumstances should you allow a spouse, grandparent, in-law, or anyone but your child to feel the temperature of the water as it will undoubtedly be too warm, too cold, or too wet.
Step 3: Insert Child
At this point we are ready to place the child into the bath. Hopefully the child is delivered to you ready to just add water. If not, you'll have to deal with taking off clothes, diapers, etc. Hint: remove the diaper only at the very last minute to avoid any messy "accidents."
Step 4: Mutter Muffled Colorful Metaphors
I forgot step 2.5: change your clothes. Hopefully at this stage you're not wearing anything you don't mind getting wet. I don't just mean with water. If you didn't have the good sense to read all the steps before you started, well, hopefully you had the good sense to know what to wear. Once in the water, the child may do one or more of the following:
- "Spank" the water
- Try to climb out of the tub
- Throw water-laden toys at you
- Unplug the drain
- French-kiss the faucet
- Try to drink all the water
- Practice the breast stroke
As with those water rides at the theme parks, you will get wet, you may get soaked. Don't let mom hear you cursing in front of the baby.
Step 5: Clean the Child
Oh yeah, do you have a cup or bucket you can use to wash the soap out of the child's hair? I guess that was step 2.6. It's just no fun if you have everything you need the first time.
You'll need to use soap in this step. I use Johnson's Multi-Purpose No More Tears and thank God for the pump action dispenser. I usually start with the hair. Cleaning it is easy. Rinsing out the soap is hard. I recommend a firm but gentle grasp under the child's neck and head with one hand, and the cup or bucket filled with warm, clean water in the other. Now, lower the back of the child's head to the surface of the water. Just as you're about to dump the clean water over her hair to wash out the soap and she squirms out of your grasp falling face first into the tub, use another colorful metaphor. "Nothing" is what you'll shout to your spouse in the other room who responded to your colorful metaphor with a concerned "what's wrong?" 
Grab the child out of the water. Make sure she's still breathing (yes, choking counts). If the child appears dazed or stunned, use this to your advantage and finish rinsing the soap out of her hair. If the child is not yet dazed or stunned...well, let's just say this works better if the child is dazed or stunned. At this point, if you had the foresight to bring a cocktail with you to this event, drink it. Use a washcloth to finish cleaning the rest of the child while she plays in the bathtub. Try to minimize the following:
- Diving
- Gulping
- Attempting to breath underwater
Step 6: Dry the Child
Here's where it gets fun. If the child has not already done so, unplug the drain. As the water drains, use the bucket or a cup to rinse off any remaining soap. Grab the towel. Stand up and stare at the child in the tub for a moment while pondering how to wrap the towel around the child without getting yourself soaked.
Good luck.
When the child gets bored and realizes she's in an empty tub and tries to climb out, the brainstorming session is over. Pick up the child and wrap the towel around her. You should now be completely wet. Bring her to the nursery and set her in the crib so she can't escape. Try not to drop her as she attempts to wriggle from your drunken, frustrated and shivering (now that you're soaked) death grip.
Step 7: Dress the Child
NASA invented Velcro for the benefit of the world, but retailers from Babies "R" Us to Wal-Mart sell baby clothes with no fewer than a gazillion snaps on each outfit. These people clearly don't have children. Begin by placing the "snappy" outfit flat on the crib. Lay the child on top of it. Try to keep her flat on her back while you wrestle one arm into the sleeve. This will involve leaning over the crib rail and cutting off blood flow to your lower extremities. When you get the first arm halfway through the sleeve and the child's fist opens up, catching her thumb inside the sleeve and stopping the arm from moving any further, curse loudly.
Stand up and look around the room incredulously for the hidden camera as you mutter "what am I doing?" Now grab onto a solid, immovable object as there will be a moment of light-headedness when all the blood rushes from your head back into your legs. Once it passes, grasp the child firmly and quickly remove her from the crib and place her flat on the floor. She should now be temporarily disoriented from trying to figure out why she is not still in the crib. Use that moment to get the first arm through the sleeve. If you haven't finished that cocktail, now is a good time.
With one hand holding the baby down, use your other hand to fish her other arm into the sleeve. If you start to sound like you're in an episode of COPS ("stay down and quit resisting!") you're doing it right. Use the same approach with the legs. If the outfit is equipped with "feet" it gets a little trickier because you have to continue to hold the child down, put her foot in the pajama foot, and snap it closed enough to prevent her from removing the first foot when you move on to the second. It helps to utter a few more colorful metaphors. It also helps if you have three hands.
Once you get both hands and both feet in place and the outfit snapped securely, hold the child upright. She may smile and/or giggle at you. This is not because she loves you or has gas. You misaligned some of the snaps and will have to redo a good portion of them and she thinks it's funny. If you finished your cocktail, you may have to redo some portions more than once. In that case you get the last laugh--unless you forgot to put on the diaper. That was step 6.5.