First and foremost, good traction is a must when attempting to urinate in public. Know your footwear! Some tread becomes slippery when wet.  Keeping an eye on the horizon is always a good idea, especially if you sometimes have a hard time determining which way is down. Remember, gravity can be your friend if you keep the spigot pointed in the right direction. If you often find yourself attempting to empty your bladder while having trouble keeping a fix on the horizon you might think about gluing a sextant to your footwear. Failing that you might think about wearing an absorbent neckerchief. Remember, only you can prevent horribly embarrassing photos of yourself from appearing on the internet. 

W.Dan