Here's a tip. Clear levels but don't worry about getting a glowing frame. Your goal is to get to level 40. When you do then max on the high grade gems. Use those to start. If you place them right they will get you through the entire level. Then add waves as needed. Use the mana pool often. This gives you the big points when you start a wave and will give you the glowing frame. Good luck.
 "GemCraft"){kind=icon}
 "Castlewars"){kind=icon}