Disclaimer: had this idea while high, didn't put in too much thought and have absolutely nothing riding on this. That being said, I have put a little bit of time in it and would like to see at least a tiny bit of sales at some point, so maybe you guys can help me with some marketing advice or maybe you have recommendations on the looks of the book series or something content-wise? So here's the whole idea (will pop a link at the end of the post): My gf's birthday was coming up and seeing as we're both broke, I was trying to think of a nice, thoughtful gift to give her. Eventually came up with an idea to make a paperback online as a substitute for a birthday card. I ended up making the thing, putting a nice picture of her favorite dog breed on the cover, named it "Happy Birthday" and got in touch with as many of our her friends and family to send me birthday wishes for her and I copied them into the interior and voila! She loved it, a lot of the people that sent her their best wishes ended up asking if I could ever do that for them to give to their SOs etc. So I figured, hey, what if I make some funny ones for my buddies' birthdays. One's that say on the cover something like "Happy Birthday, You Sack of Shit!". So I did that. I haven't marketed them at all, in any way, mostly because I have a full time job, plus I spend ALL of my free time doing stand-up and writing jokes for that, so there's not a lot of time left over for this. If you guys could drop some feedback for me, that would be awesome! 
Here's the link, so you know what it looks like: https://www.amazon.co.uk/dp/1548219967/ref=sr_1_1?ie=UTF8&qid=1499195404&sr=8-1&keywords=r+j+duncan
Here's the link, so you know what it looks like: https://www.amazon.co.uk/dp/1548219967/ref=sr_1_1?ie=UTF8&qid=1499195404&sr=8-1&keywords=r+j+duncan