Cheat Sheet - some tricks for writing

My friend Laura, an salvadorean-canadian anthropologists living in Regina, Canada, sent me recently via regular mail a Cheat Sheet for some tricks on writing "I picked up during several years of English courses".
1. Sentence variation (using long and short sentences back and forth) is good, but English is a language where shorter sencentes generally work better. So no 3 line sentences!
2. Use LOTS of transitional devices: furthermore, however, likewise, for instance, also, however, etc. These will improve the flow of your writing and will make for a much better reading. They were always my saving device.
3. Don´t use double negatives.
I.e. We don´t have no access to water (incorrect)
We don´t have any access to water (correct)
4. Try not to use contractions, especially for formal writing... so cannot instead of can´t or did not instead of didn´t.
5. Invest in a decent thesaurus. I plan on taking this advice one of these days.