Try to not spend a lot of time focusing on the difficulties of staying quit. If you do have these thoughts, view them as steppingstones bringing you closer to your goal, or as opportunities to practice new thoughts or behaviors to deal with life challenges. It helps to shift your attention to other things. If you're at work, turn your concentration to the task at hand. At home, get involved in a project, read something, watch TV or take a short walk. A short nap can help if you're feeling fatigued. It can be as simple as focusing your attention on your surroundings. A phone call to a friend, especially a non-smoking one, is an effective tool against 'addictive thinking'. It takes practice.