Find an environment where you can use your strengths to improve motivation, focus & attention

Self-determination theory posits that being aware of yourself will help you remain self motivated without the need for external rewards.  Self-awareness is one of the 11 components related to self-determination theory that address intrinsic motivation.  

Self awareness means that you understand your strengths and weaknesses.  Self awareness builds self respect because you will be willing to work in an environment that support these aspects of yourself and thrive.  Therefore find work that you are good at and where you can delegate work you are not so good at to other people.  An environment that supports this structure would have to include people that won't mind your own shortcomings but their own too. Finding an environment that supports your strengths and working in a team that will distribute work that you are not so good at to others will help you stay focused and attentive.  

A supportive environment and team also means providing a structure that will provide accountability, meaning standing by your decisions and actions.  Each decision and task completed will help complete the overall goal and vision of the team.   If you fail to focus on your goals, then you fail the team.  People who tend to respect their manager, colleagues and the vision of the company are more willing to work hard and cope with the challenges because where they work, who they work with and why they are doing the work provides intrinsic motivation as it is important to the person.    

In summary, it is important to work in an environment where you are respected, respect others, understand each others strengths and weaknesses and delegate work you are not so good at to remain stimulated and engaged.