As a self-motivated, conscientious worker, regular self-assessment is already a part of your routine. In addition to identifying your strengths and weaknesses, use this self-evaluation time to document–in writing–your achievements. Keep track of things such as:
Projects you’ve undertaken outside your job responsibilities
Any money- or resource-saving ideas you’ve implemented
Outstanding successes on any of your projects
Training you’ve received, especially on your own time
Plan towards the time when you’re going to ask for a raise. Setting a deadline for yourself will focus your efforts and give you added encouragement to keep working at a high level, even when there’s no immediate payoff.