Things to do in Niagara Falls?

The American side has a great park and you can walk up to the edge of the falls. I like the Cave of the Winds tour on the American side much better.

So, tour the parks on the American side, do the Cave of the Winds, and the Observation Tower and then cross over to the Canadian side. You can see the falls better and there is more to do that isn't falls related.

On the Canadian side, walk around to look at the falls, go through the Butterfly Conservatory and whatever tourist stuff you want.

Maid of the Mist can be done from either side. That's a must.

Niagara on the Lake is close, there are wineries (try the Ice Wine) and better places to eat and lots of small shops to take your money.