Answer:

Apply this concentrating-like-a-laser “campaign”:

Before starting the task: 

1. Visualise doing all the right things:  Spend a few seconds visualising yourself:
   *  focusing like a laser;
   *  shooing away unwanted thoughts;
   *  resisting the urge to stop the task prematurely;
   *  ignoring any distractions;
   *  sitting yourself back down and getting back to work should you suddenly decide to “escape”!
2. Remind yourself why this task is so important: Our mind focuses well on things it considers to be important.  Therefore, you need to convince your mind this task  is very important.  The better your mind believes this,  the better it will focus.  Before starting, tell yourself:
   “This task is important. I will throw myself into it because  I want to do it well.”  
3. Set the intention to focus well –and believe you can focus well:  If you commit to focusing well and you believe you can, then you probably will.  It’s as simple as that!  Tell yourself:
   “I’m going to focus like a laser on this.  I’m going to concentrate only on this task, nothing else.”
4. Set a challenging but achievable goal: You’ll focus better if you set yourself a goal–a production goal or a time goal — or both:
   *  I will finish this report in 30 minutes.
   *  I will work on this task for 60 minutes.
   *  I will write 1000 words.
   *  I will keep working until I’ve written three letters.
5. Take caffeine: Caffeine is proven to boost alertness and reasoning skills.  Caffeine  is too  wonderful a brain stimulant to be wasted in purely recreational activities in coffee shops!  Time your caffeine intake to kick in when you’re working on something you really want to focus on.  I don’t like coffee or tea or cola drinks, so I take half a caffeine tablet (the equivalent of half an espresso).  I find even that tiny amount helps me to focus really well.  And maybe because I genuinely believe the caffeine helps me to concentrate, this positive expectation offers extra help to my concentration powers (see point 3).  
6. Dial up a sober, serious mood.  The best mood for doing serious cognitive work is a sober, slightly sad mood.  Too much exuberance makes our brain too flighty; too much sadness or anxiety or anger spoils the focus as well.  So just before to start work, spend a few seconds telling yourself:
   “Settle down, sober up, and get serious.”
   
7. Set things up to minimize distractions:  Distractions are a killer when trying to focus like a laser, with just  the tiniest distraction capable of breaking the spell.  Spend a few seconds anticipating  potential distractions, and deal with them before starting work:
   *  Turn off email alerts.
   *  Put mobile phone on silent; switch regular phone to answering machine.
   *  Use headphones that play white noise or shut door to block out  other people’s noise.
   *  Satisfy your bodily needs beforehand, e.g., hunger, thirst, toilet, feeling too cold or too hot.
   *  Anticipate the things you’ll need to do the task, and get those things ready beforehand. 

 

During the task: 

1. Tell your brain to keep focusing on just the task:  You’re not concentrating if your mind darts from your work task to other things–especially if those other things are anxious thoughts.  Tell your brain:
   “Look,  I can’t think of all these things at once!  I promise I’ll think about this other stuff later, but right now I must spend this next 60 minutes writing this report.” 
   As the distracting thoughts come in, just say:
   “Shhhh…Go away!”.
   If the thoughts are very insistent, write the issues down so your brain knows you won’t forget them.
2. Apply the five more rule:  If you’re tempted to stop prematurely–perhaps because your work has gotten a bit hard or boring–make yourself apply the JUST FIVE MORE rule:
   *  Just read FIVE MORE pages.
   *  Just write FIVE MORE sentences.
   *  Just work FIVE MORE minutes. 
   Hopefully, while you’re doing FIVE MORE, your “mental-stamina second wind” kicks in and you’re happy to keep on working.   The added benefit of doing the JUST FIVE MORE routine  is that you learn to push through your frustration point and build up your long-term concentration span as well as building up your perception of  yourself as an ace concentrator.
 

 

3. Get back on task if you catch yourself escaping:  You might notice that you suddenly get up and go off somewhere–maybe to get something to eat.  Or you might stop your task and start checking your emails. I notice I do this unconscious ” escaping”when I get over-stimulated from writing or when it gets hard.  When you catch yourself “escaping” like this,  just calmly tell yourself:
   “Go and sit down again, re-focus and get back to work! It’s not time to steop yet.”