To set up good writing posture.

1. First of all, you need a keyboard with a cord or Bluetooth (something other than just a laptop keyboard). This will help you change positions while writing, which will make you more comfortable. Not to mention, a stand-alone keyboard has better spacing and is easier (at least, for me) to type on.
2. Once you have that, you need to sit down on the edge of a couch or chair, put the computer on a chair or to the side on the couch also, and then make sure you have elbow room.
3. Sit up straight, with your keyboard on your lap and let the good posture enhance your keystrokes.
4. Eventually, you can lean back, once your fingers are comfortable on the keyboard. And even close your eyes if you need sleep. Just try to pay attention or you’ll start writing down that stuff that plays across your mind just before you go to sleep. It’s quite interesting to see it happen, actually.

Try this all if you can. The posture immediately makes my keystrokes firm, more precise, and heavy. Eliminate clumsiness by being poised for action.

Fast striking keystrokes prove that you, the author in the room, are fire.