1 per day: If you have just started blogging, then writing consistently might take time. So set a target to have 1 post per day that is well researched.
Post Ideas: At times you will just run out of ideas for post not sure what to do. use google and apps like Evernote to note down all that ticks in your mind. Something will surely turn into a new post.
For E-commerce bloggers, it is essential to define your audience and take worthy steps to reach out to them. This will be the sole determinant of your marketing plan.