Hints requested

I played the demo of this game and enjoyed the concept. Much different than other match 3 games - besides the obvious fact it is a match 4. But while playing the hour demo I did not get much higher than level 10 on any game because I wanted to check out the 3 separate types of games. I enjoyed two of the three other games so I purchased the game.

I believe I read there are over 100 levels so I would expect the game to get very difficult around level 75 or so. However I found the levels getting very difficult around 17! I managed to finally get to level 22 before it is just impossible with the limited time to go further.

I have had success with many other games like this one so I am guessing I am missing something? I know you can match more than the four corners - for example the diagonal lines can be 7 long. I know to rotate the board - but find that doesn't help much.

I fear I am suppose to rotate the board before I make a match to see how the board will refill itself, but that would take a great deal of time that I just do not have.

Any suggestions or hints would be appreciated.

Thank You.