Knowing German grammar sort of helps before starting on Japanese grammar, I think - that's what I found, well with the sticking the verb at the end of sentences and stuff anywayI did not like the fact nouns can be one of three genders in German though, too much extra stuff to memorise
German is far easier to read than English though - you pronounce absolutely every letter you see (the German way, of course) unlike all the weird stuff in English