#10 Not answering to Comments
People take the time to comment on your blog so you should at least answer their questions or somehow thank them for visiting your blog.
#9 Too many Ads
If you only blog to make money with the help of ads your blog design will be afflicted. If you want to advertise on your blog make sure that the ads are interesting for your readers and that there aren´t too many advertising widgets.
#8 Unrelated Comments
If you don't read a post then you shouldn't comment on it. Don't you think it's quite embarrassing to write "I love your outfit" when the blogger clearly stated that it's her sister's/friend's outfit?
#7 Sparkle, Snowflakes and "Funny" Mouse Cursors or Using Smileys in your Posts
If your blog design looks like a birthday party no one will take your content seriously. The same goes for smileys. At times it can be hard not to type the famous ":" and ")" but there are other ways of expressing irony and cheerfulness.
#6 Unclean Design
When arranging your design you should make clear that your texts are easy to read and that your design doesn't detract from your content. For example black backgrounds with pink font seem to be quite unpopular.
#5 Music Play lists
Play lists can be really annoying for example when you are listening to your own music and have opened several tabs and don't know where this new music is coming from. Also please consider that everybody has a different taste! If you want to add music to your blog you should do so by Youtube videos which we can play if and only if we want to.
#4 Spelling Mistakes
Nobody is perfect and most of all nobody's grammar is perfect but you should make sure to use the spell check (for blogger blogs it's the little tool that says "abc✓" in the tool bar over your post window) to avoid the crudest mistakes.
#3 Advertising your Blog in Comments
If you just comment on order to advertise your own blog people will notice. If you want to advertise your blog please do so on Facebook or other social networks. The comment form should only be used to leave relevant feedback on a blog post.
#2 Follow-for-Follow Requests
If your blog has a good or interesting content people will follow you, all you need to do is advertise (see #3) it and be patient. Asking people to follow you brings them in a double bind if they don't like your blog enough to follow it. Also if at the end of let's say a year you got a lot of new followers by asking them to follow you, how can you know who really likes your blog and who doesn't? Also people that just followed your blog because you asked them too will probably forget about your blog quite quickly and not read it and this can't be what you want to achieve, right?
#1 Captcha Code
I know it helps to prevent spam but a lot of people think it's annoying to fill it in so if you want more comments you should think about removing the captcha code.
I think we're all guilty of the one or the other point, for example I had the captcha code for such a long time even if I disliked it on other blogs. However let's not forget that if you like the one or the other mentioned aspect on your blog then why should you want to remove it? Because after all the first person that should like a blog is the blogger him/herself!
I hope that this post was helpful and that it wasn't too offending for the one or the other but if you want to take your blog to a more professional level you should really consider some of these points. Which blogging faux pas have you been committing so far? Are there other things that really annoy you in the world of blogging? Oh and I almost forgot the most important question: do you like this kind of posts and do you want me to write more of these?