2) Interleaving

One strategy for learning is blocking. It involves practicing one thing at a time before the next ( Learning topic A before B, before C forming the pattern AABBCC), in interleaving you mix several topics together (forming the pattern ABCABC)

It may seem a little harder as it can take a bit longer to learn material. But it can generate better and long-lasting results. It is important that when using interleaving method you shouldn't switch between subjects too often, it's all about getting the balance.