Best type of meditation for attention
You might want to try Samatha meditation. This type of meditation would have you fix your attention on a single object of meditation over a period of time. The common object is your in and out breaths. The point of focus is usually the tip of the nose or the upper lips where you could feel the in and out breaths making contact. Since this training requires you to stay with a single object over a long period of time, it could help your mind maintains a higher attention span and lasting focus on a subject. Sutta reference is available here and a detailed analysis is available here. Good luck..