First you have know the how to go from a chemical name to a chemical formula. It helps to memorize a list of common anions, as knowing their charge and formula is useful when "decoding" the chemical name. (Chemistry Nomenclature)
Then you have to know what a net ionic equation is, which is basically a chemical equation that shows all of the charges of the ions in the chemical formula of an ionic compound.
The primary use I have seen for net ionic equations is for more concise way of describing precipitate reactions. A precipitate reaction, by definition, produces an insoluble compound as well as an aqueous ionic solution.
Using a solubility chart will help you identify water soluble and water insoluble compounds.
a.) Ag(+)(aq.) + NO3(-)(aq.) + K(+)(aq.) + I(-)(aq.) --> AgI(s) + K(+)(aq.) + NO3(-)(aq.)
In this first example Ag+ and I- form Silver Iodide, an insoluble compound. The remaining reactants are re-expressed on the product side of the equation in their "ionic form", as K+ and NO3-.
For a list of helpful solubility rules:
2(NH4)(+)(aq.) + S(2-)(aq.) + Pb(2+) + 2(NO3)(-) --> PbS(s.) + 2(NH4)(+)(aq.) + 2(NO3)(-)(aq.)
I'll let you do the rest, however if you need more help feel free to ask.