The gun debate is at its root a diversion from the debate on crime control.
Over the last 50 years we as a nation have turned how we treat crime and criminals from a social concern to one almost completely of being "tough on crime". So instead of treating violent crime as a symptom of greater social underlying social ills; we treat it as if it was a sourceless event, divorced from any back ground.
Thus we are met with the ludicrous site of adults arguing about how to treat the symptoms while ignoring the underlying disease.
One type of crime is gun related violence. Since we can't treat it as a social problem and the only socially acceptable policy is being tough on crime; we have to treat firearms as magical talismanic objects. On the one side guns are gremlins that madden those who come into contact with them, making them commit irrational acts of violence. The other side has been reduced to believing that firearms are metallic guardian angels, the mere presence of which make crime disappear.
To be involved in the gun law debate almost requires magical thinking and magic is only effective for Harry Potter.
The most important thing people should be aware of with the debate over gun laws is that both sides are sucking air out of our nations ability to address our problems with crime in an effective manner.
Now for some practical debate stuff.
I feel that it is important to have an over arching theme to your debate. Don't fall into the trap of thinking of each part of the debate as independent from each other.
I would use the theme I described above, placing the onus on my opponent. For example, "My opponent wants to spend valuable tax dollars on a program of doubtful constitutional validity and doubtful effectiveness when
http://www.fightcrime.org/ has released a study that indicates simply having children in daycare reduces crime by as much as 50%. Why is my opponent wasting our time?"
Your opponent will no doubt be just as dedicated to winning as you will be. They can't win in you are the one who defines what winning is. So define what your opponents end game is, what they would like the world to be like if they got everything they asked for. But stretch it to the point of absurdity.
For example, "My opponents want a world without guns in which there is no gun violence, criminals get decent jobs, everyone is nice, and each child gets a puppy. I would like a puppy to."