Oldest tip in the book but it works. Having a neat schedule with time allotted to tasks to follow gives you clear motives and helps you not get distracted. 

Always have clear goals and keep them realistic to avoid getting overwhelmed. Know your strengths and weaknesses and set goals accordingly. 

Keep your workspace and surroundings organised and clutter-free. A clean and tidy workspace makes you more productive and focused. 

Having deadlines for your tasks makes them a priority and creates a sense of urgency. 

Try not to give in to temptations and distractions. Learn when to say no and try to distance yourself from things that take your attention away from your tasks.