“Express your most powerful thought in the shortest sentence” is pretty solid advice.
The above quotation is taken from:
Check it out. You will learn something. Or you might find the advice glib. But do consider it.
The advantage of short sentences for your main idea: no one will lose your thesis is a forest of other ideas.
The disadvantages: it can sound like brow-beating, a harangue or politicking. In other words, expressing complicated ideas in short, short sentences is often over-simplifying. Nobody can express nuance in a five-word sentence. As I hope to have shown in the “Check it out” series of sentences, a series of short sentences is death to rhythm.
On a side-note: keep your e-mails brief. If you want to ask me something, don’t hide the request within 150 words of fluff. Just ask. Be direct but not accusatory (stay tuned for more on this).
Also, check out last year’s series of language notes at:
http://www2.arnes.si/~bjason/LNW.pdf
101 English Tips: A Quick Guide to Avoiding “Slovenglish” is available at:
http://www2.arnes.si/~bjason/101%20Tips%20-%20BLAKE.pdf
and (in a groovy page-turning form) at:
NOTE THAT 70% OF STUDENT MISTAKES ARE EXPLICITLY COVERED IN THESE GUIDES.