Team building help?

So, I need help building a good pokemon team and this is what I had so far for an idea: [u]Special Sweeper[/u] -Porygon Z [u]Physical Attacker[/u] -Electivire [u]???[/u] -Skarmory [u]Entry Hazard Clean Up[/u] -Starmie I'm not sure what else to use as I was thinking of getting some walling pokemon and then another to just set up stealth rocks or something.