Anis – I think that most consistent bloggers are simply “being who they are” even if it doesn’t seem that much on the surface. So they can jot down their thoughts once in a while without much stress. Eg there are people who can happily rant for hours, and I just adore those blogs. There are people who post interesting snippets of their everyday lives along with an insight or two, in a very relaxed manner. Their audience might be smaller, but it’s bigger than the average audience of a dead blog.
Another way is to write several articles over the weekend and stack them up for the future. It never really worked for me, but there are people for whom it goes brilliantly.