"Leaking"?-I haven't had Seal leaking problems. I'm assuming you take your Tank completely apart, inspect and clean everything throughly (Vodka works great)
A tip from the Aspire Site- Apply a few drops of your eLiquid to the Big Rubber Seal on the Base before tightening the Tank and Base together. It makes it easier to to thread the Glass snugly against the base and it also makes it easier to take it back apart too.
"Flooding"- When I was using BVC coils they would flood constantly, and occasionally my juice would leak out the bottom of my Tank.Flooding can make for a funky burnt wick taste also,but it's not actually a "Dry Hit".
Over filling the Tank can make a leaky mess also. You should fill to between the 1ml and 2ml marks (When you flip it upright it will be right at the 5ml mark).
The issues I've had with "Dry Hits" ?
When my juice was too thick to Wick properly- A couple of drops of Distilledwater or Vodka fixes that.
When I'm Marathon Chain Vaping

When Ive run the Tank too low
When I've set the power too high- I set mine now at 6.5 W and 3.3V using a 1.8 ohm coil and get the optimum flavor for me.