An acronym is a word formed from the first letters of a series of words. Acronyms are used frequently as names of organizations or abbreviations for dense scientific terms, but they also can be crafted to use as a mnemonic tool. For example, the acronym HOMES is often used to remember the great lakes: Huron, Ontario, Michigan, Erie and Superior. FOIL helps algebra students remember the steps in factoring: first, outer, inner and last. Acronyms are great for basic memorization but do not help with comprehension learning.
Acrostic mnemonics is similar to using acronyms. Instead of creating a word out of the first letters of several words, you create a sentence out of a group of letters. For example, the sentence "Every Good Boy Does Fine" (or similar variations) is a tool used to learn the notes of the G-clef (E, G, B, D and F). A more complex acrostic sentence is one where you take the first letters from a group of hard-to-remember words and create a new sentence.
Rhythm is a natural memory tool. Think about how much easier it is to remember the lyrics to your favorite song, in contrast to a similar amount of dense information. A well known rhythm mnemonic is learning the alphabet to the tune of "Twinkle Twinkle Little Star." Rhythm, like acronyms, is a good tool for rote memorization and long lists.
Loci is a slightly more complicated mnemonic technique. It involves placing items you need to memorize in a location in your mind. When you use the loci technique you picture a series of images based on a location, such as your house or daily walk, then connect the items you need to memorize with those images. This is a useful tool for remembering things in a particular order. For example, the first item in the order would be associated with an image at the beginning of your walk. You can also add a story to the process.