Dry Hits.

• Lower Wattage: If you're getting dry hits after a few pulls, the wicking may not be able to keep up because the wattage is too high.
• Loosen cotton. With a needle or pin, loosen the cotton or poke a hole through it to help improve wicking. Careful not to disturb the coil!
• Improper priming. With a new coil, priming it is important: A few drops in the wick holes, letting it sit 10 minutes with a full tank, and then slowly ramping up the wattage.
• Change coil. Bad coils could be the culprit.
• Loosen the pyrex tank. This has reportedly worked for some people. Grasp it from the bottom part of the glass tank and twist it slightly until air bubbles start to rise from the wicking holes.

Spitback.

• Higher wattage. Will vaporize e-liquid faster. Can also slide a q-tip down the chimney to wick away excess liquid.

Bad Flavor.

• Break in period. If it's a new coil, this is common. Uwell uses a fluid to keep the cotton fresh. It will go away quickly.
• Change coil. For an old coil it's a sign to change the coil.