This will happen naturally as you play enough. I hit 1,000,000 at Level 20 without replaying any levels. Your results may be different.
Always shoot for high scores. Here are things that help:
- Make and use power crystals (windchill, iceberg, glacier)
- Finish levels with lots of moves left
- Combo moves and cascades (side-by-side matches & matches that occur immediately after your initial match)
- Speed multipliers (make several matches in rapid succession)