This article by Regan A.R. Gurung and Lee I. McCann from the Association for Psychological Science outlines several effective study strategies in addition to several ineffective study strategies. The effective strategies include techniques such as creating examples that apply to the material, generating mnemonics and mental images, using a study partner, and self testing with the review questions at the end of a chapter in the book. All of these methods require elaborative rehearsal. They require the student to think about what the material means and make connections to material the student already knows as opposed to simply relying on rote memorization. Making connections and thinking critically about new material makes it much more likely that the student will remember the new material. In contrast, the ineffective strategies the article lists, such as spending too much time on key terms and summaries to the extent that pedagogical aids are ignored, highlighting too much, studying with a friend without testing each other, and using review questions as content rather than an opportunity to test knowledge are all tasks that require maintenance rehearsal. This is a more mechanical, rote memorization process. This makes it much less likely that the information will be remembered and understood. However, all of these tasks could easily be tweaked to create tasks that would require elaborative rehearsal. All in all, deeper level processing is integral to memory because the ability to retrieve a memory later depends on the memory connections that were developed during the process of encoding. In order to retrieve a memory, you must be able to rely on a number of connections, each of which triggers another connection, which leads to memory retrieval. This is why mnemonic strategies are effective; they depend on these connections.
With this in mind, I would suggest writing journal entries relating material from class to material from other classes as a way to learn and study material. It requires elaborative rehearsal due to the need to think about the material in a different way in order to connect it to other classes, possibly in different disciplines. It would also be effective to relate the material to previous material from the same class. Both tasks would serve as an active learning process that would create connections and facilitate later retrieval. This strategy would also serve to solidify understanding of concepts in the other classes to which the student was relating the material. It also forces you to put the concepts into your own words while learning and studying material; this is an important skill to have because it also aids in memory retrieval, as it requires elaborative rehearsal.
Lastly, it is also important to note that another important element of learning and studying is attention. As the article mentions, it is not beneficial to study while engaging in distracting activities such as watching tv, texting, or using social media. This is due to the fact that we have limited cognitive resources. If we are dividing our attention between multiple tasks that require similar resources, such as texting and reading a textbook, we will not be able to encode the information as well because some of our cognitive resources will be devoted to texting.
To sum up, the best study strategies are those that require elaborative processing, or making connections and thinking critically about new information. It is also best to engage in these study strategies when you are devoting all your attention to them.