The most important rule i would say is to blog because you want to. If the only reason you are blogging is because everyone else is doing it or because you hope to get lots of readers and then get sponsored or something, then its the wrong reason.
If you enjoy blogging and you do it for your sake and you invest time in your blog, then i am sure others will see that as well.
But also, if you pick a topic/theme which you are interested in and enjoy then you can stick to that and your readers will know what to expect on your blog. My blog went from a struggling, depressed, depressive blog to a recovery blog. And now more of a personal/advice/help/food blog... but you still sort of know what i will post. You know that my blog isnt the place you go if you want inspiration for fashion or interior design or you want advice on a new car.
Readers like knowing that there is a theme and topic that the blog follows. If i follow a blog and one day they post about interior design the next day about music and the next day a list of things to do when you're bored etc then i dont really like it. I prefer when the blogger keeps to sort of the same thing. Though this is just my own opinion.
Be personal on your blog... people like pictures. They like getting to know the person behind the blog. You have to be willing to share parts of yourself on the online world..If you start off anonymous soooner or later you will have to become more open if you want your blog to develop and get more readers.
I suggest blogging 2-5 posts a day.. but maybe once a day is fine in the beginning. It can be hard to think of ideas in the beginning. But be creative, write out ideas you would like to write more about. Or just sit and write some of your thoughts... not all of my posts are super clever or well thought out. They are just a ramble of thoughts, trying to put my ideas and thoughts into words.
Comment on other blogs! Get your link out there... ask to write a guest post or do a sort of shoutout on each others blogs.
However DONT just comment on peoples blogs like... I love your blog. Follow mine. and then post your link 5 times. Or always comment on someones blog and never really commenting about what they have posted, but just commenting so people see your blog link.
Dont do that. Its annoying... both for the blogger and other readers. (Though its different if you are actually commenting about what the person wrote about... because then it means you have read the persons words and are taking time out of your day to comment which is a sweet thing! :))
When you get more readers you might have to adapt your blog a little... maybe try post more or not be as repetive with posts ( haha, im guilty of this!).
Interact with your readers as well, try asking questions or asking what they want to read about!!
Remember that blogging and having followers/readers takes time... it wont happen over night. You cant force people to like your blog or read it. They choose to read themselves because they like what they see and everyone has different likes and opions. The best you can do is be proud of your blog and your writing or photography or whatever it is you are posting!!! Give it time :)