Level 47 has that points objective that seems impossible because the game gives you so few moves to reach it. What nobody mentions is that the special combos (the pieces that explode when you make a match of four or five) are the only thing that actually racks up points fast, so you have to play thinking about where the tiles are going to fall next, not just the match you see right now.
The practical thing that works: when you see you're not going to win with the moves you have left, don't keep wasting lives. Close the game, wait a day or two, and try again. It's not that the game becomes easier afterwards (that whole thing about it "adjusting" is more of a myth), but your head rests and you see the level differently. Sometimes you come back with a different strategy and suddenly it clicks. Also, take advantage of those times when the game offers you free lives for connecting with Facebook or completing other things - it's not much but you rack up attempts without spending.