Interleaving is great. After reading about this a few months ago, I realized how I did Anki was bad. I had separate decks for each subject. To interleave, you could put everything in one deck, but you'd only be able to organize by tag then.

I figured out a better way to interleave in Anki. Create a filtered deck which takes X random cards from all your other decks. You can make X as big or small as you want.

Incidentally, this also made me realize how much of a cue studying by deck was. The subject of some cards was no longer obvious because of how I wrote them, so I've slowly been disambiguating them. This is good, I think, as in reality you often don't have such a strong cue that says "use knowledge from X subject".