There were over 40 responses to a recent Quora question about improving your cognitive and concentration skills for better productivity. The poster was lamenting his diminishing ability to focus and late nights. Here's an list excerpt from the first answer
• Remove distractions
• Sleep properly
• Prioritise work
• Deactivate facebook for 10 days
• Keep at it, slow and steady wins the race.
There are several other great answers, making this page basically a repository of new productivity advice articles. Read through some of them .