http://www.lolking.net/search?name=gragasgod
http://www.lolking.net/summoner/euw/33350919#ranked-stats

Nothing personal, but you're 1-7 in silver with gragas this week.

That being said, I see a lot of errors in your guide. It's generally unpleasant to read guides with no coding. I don't code much myself, but I try to be brief and succinct in how I convey information. Your writing is a bit muddled.

In terms of the guide, it's not totally awful, but I would try to max a skill at level 9, 13, and 18. Your choice what to max, and I believe it's matchup dependent.

I also think you should consider armor seals and mr glyphs. It makes your early lane much much easier and the 16 ap you get from your seals and marks is NOTHING compared to 13 armor and 12 magic resist.

Not perse, many gragas players max W > E

It's undoubtefully better to max Barrel Roll at level nine and Body Slam at level 13.
Besides, you have to select Block in the defense Mastery Tree to be able to select Unyielding and so I suggest you to leave out th two points in Enchanted Armor .
Greater Glyph of Ability Power is messy and Greater Seal of Ability Power is pretty bad tbh because you definitely need resistances ...