Start with understanding and doing your assigned task. Remember, taking the first step is always difficult, but if you do not take that one step you can never achieve your goals. Don't get worried with the task assigned, if it is new to you. Ask required questions to better understand assigned task. Once you get started, everything will come in easy.
Bad health can also be a possible reason for being unproductive. Before you go to work; take your breakfast, rest well and research about your duties.
Make an appointment with yourself
Give yourself at least 30 minutes during the day. This will enable you to concentrate and focus your attention on the matters at hand. Give yourself time to think and concentrate as you tackle your job and projects. These uninterrupted 30 minutes will give fruitful results in the long run.
Utilize your prime time
We all have a specific time of the day when we have lots of vigor and zest and a greater ability to think and concentrate. Work out when you have your high energy levels and tackle your most important work at that time. Try to arrange meetings, appointments and other activities at another time of the day.
Avoid unplanned meetings
Spontaneous meetings are real interrupters as well as huge time-wasters and productivity destroyers. They break your concentration, disturb your thought process while undermine your momentum. The next time someone comes into your office or sits by your desk and start making him/herself comfortable, say that you are in the middle of an important project. Then ask if you could get together at a mutually convenient time later in the day or week. This is called a polite excuse.
Schedule your meetings with staff and colleagues
In most offices, time is wasted when people get up from their desks to ask their colleagues a question. Fix a specific time to meet colleagues for queries. Best is the time slot which does not fall in the peak hours of work.
It is a fact that taking breaks periodically during the day relax your body and nerves and refreshes you for the tasks ahead. Ensure that you take small breaks all day. It could be a walk to the water cooler from your office/room or a visit to the photocopy machine/fax/ printer.
Establish a routine of listing your daily and weekly tasks. This will allow you to have your most productive week all the time. Start your day an extra 15 minutes early to do this planning every day. Write down the top 3 important things you must do that day. Plan your upcoming week on Sunday evening.
Drop unimportant tasks
Delete the non-essential items from your to-do list. The best way to do this is to prioritize and complete your most important things first.
Enjoy your time at work
Being productive and competitive in official business doesn't mean that you have to be serious all the time. Smiling doesn't mean you're not working hard. Be enthusiastic as well as competitive. Stay positive, that way you can face and win challenges better.
Be a Team Player
Don't be afraid to collaborate with others. Don't wait for your boss to tell you what to do.
Learn from criticism
Be a sport and never immediately reject critiques from others, even if you do not like or respect them. Sometimes people you do not like may be giving you more honest feedback than you can get from others.
Adapting is in the nature of living beings. Those who do not adapt, become extinct.
Upgrade your learning
Always be on the lookout for opportunities to learn and improve your skills. Look for good seminars and training.
p/s: Lots of tips here, some i just can't do yet. It takes time...