Here are some things that we did during that period of 12-16 months; :)
We tried to avoid giving snacks so she would really want to eat when given something.
We ate dinner together (as often as we could) as a family, she would watch with an empty bowl and spoon, and make sounds from her feeding chair.
We would increase interactions with her as the banging got less and gargling googling sounds increased ( sounds robotic but it really wasn't )
With hand and eye movements we would ask " Want a taste?" "yes" "no" etc...This was quite fun and we would give her bits of vegtable that she could chew. Of course sometimes the vegtables were thrown on the floor, so we would do the "no, thats not nice now is it" and go back to eating our food. The throwing thing didn't last long, and dinner times were smooth, we had 10 t0 15 minutes to eat while she was happy drumming, and then whoever finished first would feed her.
This worked for us quite well, soon after we took bigger risks by giving her a pot of yoghurt and a spoon. It was fun watching her.