Keep watching for interactions . Two birds together will often blow up the whole board, which saves moves and gets you lots of points. watch the bright circle expand with each time you clear an area. When you close the ring, it will cast fireballs to...

The fireball keeps track of how many gems you have eliminated. When you make a big play it circles faster. EAch time you close the circle, it will discharge some flares to wipe out one or more targets. 

Watch how the circle closes more quickly when you make a big play, like joining two birds and triggering them. Each time the circle closes, you get one or more obstacles removed. But I find it very handy when I have just one or two tricky - stubborn ...