Space Plan for space between where you want the cup/pitcher/bowl to rest and where you have your spout. I find it difficult, especially for young children to be able to hold and turn the dispenser on and off. Having a space to rest makes a big difference. Just make sure there is adequate space for something to rest and not be crammed or knock over the dispenser.
Tray for Drips Spills/drips/accidents/leaving the spout on will happen. Just accept that. IT WILL HAPPEN. But, you can start to minimize the mess by placing a tray/bucket under the dispenser. We have a small tray with raised sides but for a younger child, or child new to such independent access, a small bucket may be a better choice. Then, you can empty the bucket/tray as needed.
Clean Up Keep some tools for cleaning up nearby. This may be a mop, or just rags for wiping up spills. Make sure your children are starting to help with this too so that it doesn't all fall to you. They will eventually start to help with the process if you are modeling clean up for them from the beginning.
Remember, that your space doesn't need to look exactly like my space. Follow your child and work to give as much independence to your child as possible!