Here are some resources to help you study more effectively.

Practical Skills

GNU Typist
A free program to learn touch typing.
How to Study in College
A textbook (by Walter Pauk and Ross J.Q. Owens) with all the study skill you should have been taught in High School.
Stanford University’s Student Learning Programs
Reaching your academic potential can be challenging, but learning effective habits can make a significant difference.
How to Read a Book
You cannot read all the books in the world. Thus, it is important to maximize what you get out of books.
Getting Things Done
A system when a simple TO-DO list no longer works.

Memorization

Moonwalking with Einstein
A story about mental athletics.
Your Memory: How It Works and How to Improve It
A great book to understand why we remember some things and forget others.
The Memory Book
A book full of memory techniques.

Grammar

English Composition and Grammar: Complete Course
A great resource on standard English grammar.

Tools

The Unix command look
Display words beginning with a given prefix.
The Unix dictionary
A Perl client for accessing network dictionary servers. It contains the Computing Dictionary.
LanguageTool
A better alternative to Grammarly.
GNU Style and Diction

diction identifies wordy and commonly misused phrases. style analyzes surface characteristics of a document, including sentence length and other readability measures.

Org-Mode for Emacs

Org mode is for keeping notes, maintaining to-do lists, planning projects, authoring documents, computational notebooks, literate programming and more — in a fast and effective plain text system.

Document Generation

Latex
The best typesetting software for document generation.
Beamer (Latex)
Beamer is a powerful and flexible LaTeX class to create great looking presentations.
Graphviz (Dot)
A great way to make simple digraphs.
TikZ (Latex package)
TikZ is probably the most complex and powerful tool to create graphic elements in Latex.