Try it this way:
H[Acetate] + Ba(OH)2 -->
You know 3 things:
1). Acetate has a -1 charge, H has a +1 charge
2). Barium has a +2 charge (second column of peroiodic table) (OH) has a -1 charge, so you'll need two in this molecule
3). Acid and bases neutralize each other into water, that's one H+ and one OH-
H[Acetate] + Ba(OH)2 --> Ba([Acetate])2 + H2O
Now, of course, you know that the barium and acetate exist in solutions as ions, like you did in your equation. But putting them together in a molecule insures that you'll balance properly. Of course, now it's not balanced, two acetates on the right one on the left, two (OH)'s on the left and only one water on the right -- how will you fix it?