Quote Originally Posted by ShakeyX View Post
Ты купила рыбу для ужина сегодня вечером (now I'm using perfective to suggest that this was PRE-DISCUSSED fish, a one time completed action as it is for tonight's dinner, and god knows I want some fish tonight).
I would rather say "Ты купила рыбу (сегодня) на ужин?"
You can use imperfective "покупала" for "Did you happen to buy the fish for today's dinner", but I'd say that's not the most neutral way. I.e. it's as if you already suspect nobody bought the fish. One more concern is the context. The sentence is much too long for actual speech. If the fish was pre-discussed, why not ask "Have you bought the fish" ("Ты купила рыбу")?

Another example I wanted to say "I have never ate solyanka so I will eat it tomorrow"... I used я поем завтра...
Here "поем" may sound as if you are just going to satisfy your hunger and move on ("поесть" has a shade of "limited amout" of action: "eat a certain amout/for a while"). For important prolonged activities you can use imperfective (after all, you are going to have an experience rather than check in after the plate is empty). I think both can be used. You can also say "I'll try it tomorrow" ("Завтра попробую").