"We forget what it's like to master a new and complicated motor task," says Sutton Hamilton, M.D., former assistant professor of family medicine at Virginia Commonwealth University. Just as we don't expect a 3- or 4-year-old to have perfect grammar, we can't expect him to walk or even eat with much grace. Your child will probably get it together by the time he's in kindergarten or first grade, but in the meantime:
Do things he's good at. So he has trouble catching a ball -- go for a nature walk instead. You can always revisit the difficult activity in a few months.
Keep him safe. Leave that sharp-cornered coffee table in storage a little while longer, and teach him to pick up his toys so he doesn't trip over them.
Don't hover. If he wants to try something new, let him. Practicing with a big-kid cup or a tricycle will help him get better at using it.