Our toilets do not flush very well. Meaning that it may take 2 or
more flushes to really flush the ****. The tanks properly fill and
properly release water, but it seems as though there is just not
enough of water to do the job right.

Toilets used to have 3-gallon tanks. Then the ecology people got a
law passed that made 3-gallaon toilets illegal (to buy new). Now we
are saving water. I guess they need a new law to make it illegal to
flush twice, but that is another issue.

Obvious jokes aside, are there any toilets that flush very well
(other than commercial style toilets that seem to have vacuum).
What is a characteristic that we should look for? Tank volume?

A 3-gallon tank might still be found at auctions and such. eBay?