I watch the bar/gauge to the left, the X flashes when a link is available. Then I'll do a quick move that I know current partner will link with, hitting R2 with it. You can get 3-5 links before gauge fills I think, before it does a link chance for bonus damage. I save full gauge for beginning of a fight.
Also, I think I've given up on charged spells. There is never enough time to cast any without being interrupted, no matter how good the link partner is at blocking for me. It's a shame because if you can pull off a fire circle linked, it does major AoE damage. I do have the game set to hard, maybe that's it. Only on bosses was I able to circle and cast with no worry, regular mobs just gang up on me.
What's up with only being able to carry 1 food dish of 1 type? Ah well, I think that's what they wanted so you'd have to buy 1 of each small, medium, large. Which promote leveling that shop. I eat a dish at shop, then buy 1 of each I use.