The following page provides some tips on how to compose academic texts.
You can learn more about academic writing by reading University of Kansa's Writing Guides, where you for example will find information on writing an abstract or editing and proofreading. We also recommend Lund University, who provides a comprehensive guide to academic writing in English called AWELU, Academic Writing at Lund University.
Paradigm: Online Writing Assistant contains general tips on writing as well as a specific guide for writing a thesis.
The University of Manchester maintains an Academic Phrasebank where you can get tips on how to craft scientific texts. This database includes, among other things, concrete examples of how to express yourself when presenting a problematic issue, or how to describe different methods.
If you would prefer to read a book about the academic writing process, we suggest that you take a look at How to write and publish a scientific paper by Robert A. Day and Barbara Gastel (2011).
Finally, perhaps a smartphone app suits your needs? AWE - Academic Writing in English, is a complete course on academic writing that you can download for free to your iOS or Android device.
Popular science writing
General tips on popular science writing
For general thoughts on how to go about writng a popular science text, take a look at the page Popular Science Writing from Lund's University (in english). There you can read more about catching your reader's attention and some useful stylistic tricks. Perhaps you can also benefit from Henrik Bränden's (molecular biologist and author) texts on popular science writing and scientific vs. popular language (both in Swedish).
Popular science summary
The Faculty of engineering (Lund University) have made a useful compilation (in Swedish) on the characteristics of a popular science summary. It's written for phd-students publishing their dissertation, but the advice is applicable on student papers as well. Keep in mind that a popular science summary is diffrent from an abstract. Read more on how to write an abstract on the page A paper's components.