Grammar Errors

In my experience in writing, I have the greatest trouble with run-on sentences, especially in my first drafts.  I have a tendency to include too many ideas or too many components in a single sentence.  As a result, my sentences become very cumbersome and difficult to read.  To solve this problem, I try to alternate between long and short sentences.  The page on the University of Richmond Writer's Web about run-on sentences is helpful because it explains common problems that writers have.  Another grammatical error that the book "The Grammar Hammer" mentioned as one of the top twenty most grammatical errors is using wrong prepositions.  I've noticed that in my writing I sometimes use the improper prepositions.  This happens not only in my writing for English classes, but also for my writing in my Spanish class.  It is interesting to see how my grammatical errors carry over from my English class to my Spanish class.