There are several websites that offer aid and extra practice to high school students.
Quizlet is a website that allows you to make up your own study guides. Simply sign up, input information, and the website automatically designs games, flashcards, and interactive activities to help you remember material in a dynamic way. Also, other study guides are posted publicly, so simply search up the topic and someone might have already created a study guide for the subject you're struggling with!
KhanAcademy provides explanatory videos and practice problems and scenarios, especially in math and Language Arts.
Crash Course is a YouTube channel that gives fifteen minute videos explaining a huge variety of topics, from subjects like World History to Physics to Philosophy. Especially excellent for history and science.
SparkNotes offers not only literary analysis and the popular NoFear Shakespeare, but also history, mathematics, and SAT and ACT prep.
Besides SparkNotes, Shmoop has chapter by chapter 'student-speak' summaries of most literature in the high school canon. It also has excellent test and college prep.
CliffNotes is a website similar to Shmoop.
Having trouble with those tricky literary terms? Literary Devices has every term you'll ever hear in class, and some you won't with examples. It also has an active discussion page if you need further help with literary analysis.
Easybib helps make sure that your bibliography, citations, and works cited pages are always perfect. Simply select citation type, input your source's information, and click cite and you'll have a perfectly formatted citation.
Desmos is a free online graphing calculator.
Mathplanet provides lessons, explanations and resources that will assist students, parents and teachers in achieving success to prepare them for the future. However, it only goes up to Algebra II.