I have a hard time baking a good batch of cookies. They are either too fluffy or too flat. I want them juuuust right! 
chill the dough. you can scoop it out onto the pan ready to bake and then chill, or chill the bowl and scoop it cold.
make sure the oven is preheated a little high, to allow for it cooling when you open it
for repeat batches, make sure the pan has cooled down again. pans are cheap, have extra so you don't have to reuse a hot pan
*sigh* I miss my big, 36" electric convection oven, hope the next house has a better stove and oven than this one. And when we finaly buy a house, you'd better beleive the kitchen will have room for a top notch range and ovens, or will be remodeled pronto!