Other than the obvious answer of first class or business class, although I am sure on many specific routes that carry 'high-rollers' you might still find yourself sitting next to other passengers (although with more elbow space). I actually don't know of any specific place where most people will not want to sit, so I am curious as to whether there are people who have often booked seats for a particular section of the plane under specific circumstances when they are likely to have a spare seat next to them compared to other sections of the plane.
- Sitting at the front section - usually allows you to get out quicker (after the first class and business flyers)
- Sitting at the back section - usually allows you to get out just as quick (if they allow exiting via front and rear exits)
- sitting near the back section - just far away enough from the back section (sometimes where children get seated) but still able to get out quickly without too much delay.
- Sitting near the emergency exits - usually the seats taken by people who want leg room (but might not get overhead luggage room near their seat)