Make sure you dry all the pieces of your cart when you clean it between flavor changes, before putting the new flavor in you want to do a dry burn by having no liquid and pressing the button for 1-2 seconds at a time a few times until you see the whole coil get red.
After doing this you want to prime the atomizer by dropping 1 drop directly on the now dry and cleaner coil. Then just pulse the button 2 or 3 more times like you did before, drop another drop on your coil and assemble and fill it. I like to wait about 10 minutes after filling so that the wicks can really soak in the liquid but it's not completely necessary.
Hope this helps!
Peej