Here is a magical recipe if you want to do better than Daniel

When you select the tiles, take care to do straights like 1, 2, 3 ... or 3, 4, 5, 6...
If your straight contains a single family then the formula for your points is
- (Count of tiles) * 3 ^ (Count of tiles).
If your straight contains different families then the formula is
- (Count of tiles) * 2 ^ (Count of tiles).
Remarks:
- * is the multiplication operator
- ^ is the power operator. 2^1=2, 2^2=2*2, 2^3=2*2*2, 2^4=2*2*2*2...
Little example:The first series from the picture below give you 9 * 3 ^ 9 = 9 * 19683 = 177147 points!
The fourth one gives you less points because there is not only one family: 9 * 2 ^ 9 = 9 * 512 = 4608 points.

Enjoy!