The following are some helpful tips for making cleaning the baseboards easier:

 Vacuum the area first. Using an attachment on your vacuum, vacuum up the baseboards and the floors directly under it, where the baseboard and floor meets. This will help remove dust and pet hairs, which will actually make the baseboards look dirtier once they are wet.
 Wear latex or rubber gloves. Because you will be working with a detergent and getting your hands wet, it helps to prevent your hands from pruning.
 Use a mild detergent mixed in water. This can be a soap and water mixture or a vinegar and water mixture that is 1 cup of white vinegar to 5 cups of hot water (but not so hot that your hands can't stand the heat). You can also use a spray-on multi-purpose cleaner.
 Many people recommend a Mr. Clean Magic Eraser for very difficult scuff marks or stains that a regular cleaning won't get out. Clorox Wands are also recommended. These are easy to hold, not as messy as water, and can be easily discarded when you're finished with it.
 Use a sponge or a washcloth. Wring it out thoroughly so you don't slosh water everywhere. Avoid using paper towels. They can snag on the boards, leaving fuzz behind.
 Don't saturate the wall or the baseboard with water. This could be damaging to the paint and could create an even bigger mess.
 When cleaning your baseboards, keep children and pets away. This is especially important not only because they can make the baseboards dirtier by rubbing against them, but pets might try and drink a bucketful of cleaning solution, or kids might try and play in it.
 If cleaning your baseboards is part of a deep-cleaning you are giving your home overall, save the baseboards for next to last, after you have swept but before you have mopped, or last. Whichever you prefer is up to you. Saving it for last means you don't have to worry about sloshing the mop onto your newly cleaned baseboards or have dust or particles from mopping fly onto the baseboards. Waiting before you mop means not having to worry about re-cleaning your floors if cleaner or dust drips down onto the newly-mopped floors.
 When you are done cleaning, you can let your baseboards air dry.
 Sometimes, cleaning isn't enough to restore your baseboards to a cleaner, fresher appearance. In some cases, scratches, faded paint, or stubborn scuff marks make it so cleaning won't help. If this is the case, you may want to consider re-painting your baseboards. Choose a high-gloss paint that is designed especially for baseboards - this will make cleaning in the future much easier - and wipe down baseboards to free them from dirt and dust before you re-paint.

These are just a few tips that will help make cleaning your baseboards easier and more effective.