Get your feet moving by lobbing
The large majority of players rarely lob. It's not that they don't like to lob - just about everyone finds lobbing fun - but most simply do not have the mobility to effectively lob, and so they don't. (Many of these players stand like a tree when they should be moving like a squirrel.) But isn't this backwards?
If you don't have the mobility to lob, why not practice lobbing to develop that mobility? It's not a hard concept; if you practice moving, you learn to move better. And the nice thing is that if you develop mobility off the table lobbing, you will also improve your general mobility, both close to the table and away. Not only that, but if you learn to lob, you add a new tool to your table tennis toolbox. Plus lobbing is just one step away from counterlooping, a more offensive and valuable off-table weapon.
Here's an article on lobbing, an article on smashing lobs, a more general article on topspin defense, and an article on counterlooping. Study these articles; you will be tested! (If not by me, then by your opponents in matches.)
North American Olympic Trials