In order to get those challenging goals, you need to do curve kicks. You do that by swiping once to kick the ball in a certain direction and then swipe again to curve it.

You don't want to swipe too fast when curving a ball. The game might not register it as a curve ball and, instead, launch another ball in that direction. So, try inserting a little pause in between.

Try to make a combo in bull's eye mode, by waiting for the perfect time to kick. You want your moving and stationary targets aligned, so that you can "kill two birds with one stone."