....then you should still start writing...and continue writing till you get some reasonable thought to develop upon. It may initially seem awkward, but it is the way to make a road where there is none. Actually, it is very simple. By forceful writing you tell or rather instruct your lazy mind that you want a good thought to develop upon...and after an effort worth it, the mind obeys.
To start with, you can write whatever comes to your mind, such as:
``Today my mind is a bit lazy. It is not responding to what I want to do. I want to write, but it is not suggesting any topic to develop upon. However, I have decided that I will make a good effort in this regard. I will see that when I get up from my table, I have a write up in my hand and post it on the Internet. This is the only valid solution to this problem. And I shall really get this deal closed in my favour.....(You can continue writing and develop on this basic structure.)"
Within two minutes of such a starting, you will realize that some thought is developing over there. The speed of writing and thinking will increase. The hand-eye coordination will become better with each forthcoming sentence. The body position will change. You will sit in a more alert pose. The urge to take a break will vanish. Rather, the interest in developing a good write up will increase. The commitment to complete the task will gradually dominate the scene of the writing table.
The energy thus generated will charge you up. This internal energy will have positive effect on your external environment. The enjoyment will gradually reach to the peak. There will be a certain ``Happier" kind of state of mind that will really bring in the blessings from your subconscious.
This will result in a better write up than what you had written had you not extracted the thought from your mind. The effort will build your writing muscle and prepare you for the similar future conditions. In this way, you will not only save your present, but also your the future.
So, Happy writing!