Translating from English to Dovahzul can be tricky, and requires a bit more knowledge of the language than translating the other way around.  As a starting point, check out the translator.  For manual translations, check out page 40 of this guide.  It covers some steps you can take to translate English to Dovahzul, and vice versa.

The translator can be found here: http://www.thuum.org/translate.php This is the fastest way of translating from Dovahzul to English and visa versa.