yeah, just look at cards from each set. what i do is everytime a new set comes out, stare at the new symbol for about a minute, then i've memorized what it looks like. just do that and it'll only take like an hour , unless you're looking at modified hten like 8 min.
but a quick way is go look at 1 card from each set, and in the bottom right there's the symbol!
just go find a card in your collection from each set and organize them in the order of release and then you can find which symbol is which when you want ot know.