It was important, at the time, to give him small amounts. So he would throw some food out, but I never gave him a big plateful. Must have read somewhere they can find it intimidating or off putting to have so much food in front of them. I would be quite happy to pick it up from the floor and hand it back (not textbook, I know!). we had stone floors which I washed every day though. If eh was clearly not hungry i would just get him out and try again in an hour.
I also made him eat alone in front of the telly, for a while, then I had to stop that as he got so distracted he forgot to eat.
This all goes a bit against what the current "fashion" is though, but I had to find what worked for us.
The biggest thing was to pretend to not be stressed about it, and not give too much praise either, but just "play it cool". On days he ate less, i would just give him more milk at bed time.
He still has a thing about textures and "mixed up" food, but i think that is still from all the reflux and vomiting as a child.
So small portions, and ignoring him. Not asking if he likes it, not encouraging him. Just letting him get on with it (or not). Nobody can eat with someone breathing down their neck! And lovely foods like a whole nectarine are great too (for learning to enjoy food). He loved fruits (mango, nectarine, cherries). You have to find what he likes. My DS lived an entire month on bananas and scrambled egg, again, not textbook, but you just make it up as you go along really, and hope for the best :)
that should probably be my motto