Grammar

For aspects of writing beyond sentences such as sentence linking and paragraphing, look also at the pages on writing.

Diagnostic Testing
A good starting point for grammar can be to check what you know and don't know.

Typical grammar labels from low to high level and go to links for tests https://www.grammar-quizzes.com/diagnosum.html

If you want to test your grammar with a reference to two books that explain grammar, this could be useful https://www.world-english.org/diagnostic_grammar.htm When you check the test, it refers you to pages from two well-known books on English grammar: Murphy, and Swan.

Grammar activities
This website has detailed descriptions of grammar and practice activities http://guidetogrammar.org/grammar/index.htm

Specific aspects of grammar
There is a good list of typical issues in academic writing at University of Bristol with links to more detail.

Punctuation
https://www.lexico.com/grammar/punctuation