Answer:
If a compound is made of a cation and an anion it is a salt by definition in chemistry.
The simplest salts are compounds of one kind of metal cation with one kind of non-metal anion. If you look at a periodic chart, there's a dark, stair-step line over on the right. The atoms to the left of it are metals and those to the right are non-metals and some of those on the steps (not aluminum) are semi-metals or metalloids.
Then, you were given, or can look up online, a list of polyatomic ions. Memorize these.
Compounds with a metal cation and a polyatomic anion are also salts. Compounds with a polyatomic cation and any anion, are also salts.