Forming Ionic Compounds

I am having a problem forming Ionic compounds.  I have been given a list of elements.  

Na   B   N  Ca    Li   Ne  P  Al     SO4    Pb(II)  NO3  Cu(I)  etc..

Rules:  Each compond can only contain two different ions.
          You can have multiples of each element.
           Formulas must represent the simplest whole number ratio between the adams of the elements.

I don't remember how we did this.  If you could show me how to do  a couple these, it would help.