These websites provide additional notes/instruction on various grammar topics and offer practice activities that give immediate feedback!
StudySpanish.com offers free and purchase activities. For our purposes, please simply choose the free options as they provide adequate support!
Conjuguemos.com is completely free and you can choose to use the resources without an account. There are five different tabs from which to navigate once you have chosen Spanish - Verbs, Vocabulary (Textbook), Vocabulary (Theme), Grammar, and Listening Activities. Simply find what best suites your needs.
Many, many students will flock to YouTube videos to assist in comprehension. This is simply a twenty-first century tool that cannot be ignored! A few videos that are of quality for additional instruction or simply another way of looking at topics are included below.
Most of his videos include a brief grammar explanation, examples completed together and finally examples for individual practice for which he does provide the answers!
These videos tend to be a little long; however, on YouTube they include the Spanish and English. He does have a website, but once again I never recommend paying for additional resources! These do not "teach" anything directly but rather offer some humor and interest while including Spanish.
The three that are still available on YouTube do teach some tricky topics in a fun way with popular songs. Conjugations Back, Reflex Your Verby and Cry Me A Verb are all excellent!