Guidelines and glossaries
The Elements of Style by William Strunk, Jr.
This influential guide plainly illustrates some good practices for writing clearly and using rules consistently. Just reading through the contents page is already an education!
ThoughtCo’s “Glossary of Usage: Index of Commonly Confused Words”
The difference between “every day” and “everyday,” “principal” and “principle,” and many more.
Set the dictionary to the default UK English or other options with the dark blue drop-down menu in the search box.
The grey drop-down menu in the search box offers various options, including a thesaurus or bilingual dictionaries.
Most useful for US English.
German <> English as well as German <> various other languages. Available as a mobile app. Creating an account makes it possible to save looked-up words.
Translated text extracts in two languages (e.g. English and German) can be compared to get a sense for how a word or phrase is used. Do however keep in mind that many of the translations have not been vetted.
If you want to improve your presentation and general oral communication skills, joining a Toastmasters club is one of the simplest and most fun ways to do so. Regular meetings include opportunities for prepared, unprepared, and semi-prepared speaking. You build on the skills you already have with feedback from your peers. Before becoming a paying member, you can visit any club in the world as many times as you like for free to try it out. I highly recommend Toastmasters from my personal experience.
Document design and formatting
If you’re not using heading styles in Microsoft Word or similar software, you should learn how to do so today. Check out Shauna Kelly’s easy-to-use guide to heading styles. For longer documents like theses or reports, also check out how to set up numbering with heading styles.