Try putting some 3-d objects on the battle mat. Don't just draw a slab of stone - put down a domino. Set a dry erase marker on end or stack up some dice and you have a tower no player can resist knocking over on the enemy minis. Sometimes players have a hard time following or remembering the entire room description and having solid reminders help.
Other things that help:
having a character whose shtick it is to use the environment, like a swashbuckler.
having a mechanism for PCs to succeed at heroic acts helps. How realistic is to knock over an old dead tree on the ogre when the PC can't even hit it with his sword? Something like hero points to spend when attempting that -4 to hit, 6d10 damage dead tree smack-down to help with the non-proficiency penalty help to keep the attempt more than just a wasted action.
having aspects of the environment that favor members of the party. Most PCs are optimized for flat, featureless planes. Difficult terrain is not good for them, underwater combat is not good for them, needing to balance during combat is not good for them. Things to tip over can be good _IF_ they have a strength where they might succeed. Having areas large enough for medium characters but not large monsters is good for them.