You can connect via Facebook and request lives from fellow players or spend some $ in range between $1.99 for 140 coins through $99.99 for 9500 coins. 100 coins give you five lives.
When you earn super jellies by connecting six or more jellies togethe they won't necessarily destroy the row or the column they're in. But they'll destroy the row or column depending where the last piece of your jelly string ends up. If you can, try to set up the final piece of your jelly connection in the same row or column as bothersome dark jelly. You'll eliminate any pieces or mushrooms that get in the way, leaving you plenty of room to take them out.
If you can't find the pieces needed to remove dark jelly from the playfield, shift things around below. Chain together a quick three-or-more string of jellies, then watch the pieces drop down. Doing this may open an opportunity to earn super jellies, or at the very least, the pieces needed to take out dark jelly.
When you see large patches of dark jelly blocked off by mushrooms, the first thing you'll want to do is get rid of the mushrooms. By eliminating them, more jellies will pour into the dark jelly spots, enabling you to take them out piece-by-piece. The more jellies you have on the playfield, the better off you are.
Try to save some coins for the end of the round. There may be boards where you simply need one or two more turns to complete the puzzles. You'll have an option to spend 70 coins, maybe more depending on the stage, to get three more turns. It could make all the difference in getting to the next level - and saving a life in the process.
Chaining together super jellies will clear a huge amount of space on the board. Try to put together six-or-more strings as often as you can, and gather up super jellies in the middle or the bottom. When you see an opportunity, chain two or more together and watch the rows clear. Also, as an end-of-round bonus, any unused super jellies will automatically explode, adding to your point total.