My strategy is:
Try to think ahead, it's not like this game has a timer to rush.
Stack the same ingredients horizontally if possible.
Try not to put the later ingredients atop of the sooner, ie. placing a bone on top of green potion, unless you know how to get rid of it.
Consider carefully where the new ingredients will be placed after it combined.
And lastly, be patient. Try to build a stack that will produce combo if you cant get rid of it easily.
At first im stuck at 200k too, but now im averaged at 600k - 1000k 