The last couple of cakes I have baked, I am having trouble with getting an even bake on them. I'm sure this is a classic problem. I am fairly new to cakes and so I am contemplating buying Wilton's bake even strips. Does anyone have any feedback on these?

What are some of the other reasons that the outer edges of the cake will cook perfectly, but the inner circly seems to not get cooked all the way? I have tried baking the cake longer than the recipie recommends, and all that happens is the outer gets overcooked, with the center still being underdone. What do you all think?