The word grammar generally elicits a lot of groans because, let's be honest, it's not the most exciting material.  But, it is important to understand and know how to use to strengthen your writing. 
    One of the best ways to acquire knowledge of grammar is to read and be exposed to the many forms words and sentence structure can take.  Still, we all know authors can and do break the "rules" from time to time and we can't always get away with their moves. 
    So, what are some options? 
    General Resources
    Grammar Girl
    This is one of my favorite Podcasts.  It has helpful, accurate, and enjoyable (I'm not kidding!) tips on grammar.  You can listen to stories or you can read through articles and examples to help you improve your writing and speaking skills. 
    Specific Skill Resources
    Comma Splices
    This is hilarious.  With these pictures, you can't not get them!