Tap and hold to have your tank move to that location. However, because you finger will cover part of the screen you may miss incoming attacks. You can reduce this issue by constantly moving your finger around to keep your tank moving all the time. Try doing this near the bottom of the screen, as the alien ships usually appear from the top or the sides. However, if you accidently tap the ad at this location, it will obscure your screen and cost you a life. To avoid this, keep your finger on the screen to prevent a second tap.
Power-ups can be purchased at the start of a level, but are consumed when used. The Magnet is useful if your tank is slow, and the Doubler helps increase your money total. Use the Golden Ammo if facing a challenging Boss.
Use gold to upgrade your tank. Upgrade the Steering Power fully on your starting tank, the Angelfire. Do not purchase additional upgrades for it as the temporary ammo and rocket power-ups collected during game play should give you enough to progress. Save your remaining gold to purchase the Ironfist tank and do not purchase it until you get a bonus coupon for it.
The airstrike is a powerful attack that begins at the bottom of the screen and slowly works it way upward. Use an airstrike to clear alien clutter from the level. Saving it to do nice damage to Bosses is always a good option.