It might sound counter intuitive that you should be relaxed when trying to run as fast as possible, but it is effective.
Have you seen how 100m sprinters jaws wobble like a jelly when they run... it's not for the comedic effect on the slow mo replays, there's good reason!
If your antagonist muscles (muscle working against your direction of motion) are tense your agonist muscles (muscles working in favour of your direction of motion) will have to work much harder.
Tension through the shoulders, hands and mind then it often transfers to the lower body.
If you are a tense runner try keeping your hands open/fists unclenched, shoulders relaxed and release the thoughts that are playing on your mind and you should see a big difference.
Hill Sprints and Lying Starts
Hill sprints and lying starts are excellent for putting you into much more optimal acceleration mechanics automatically!
I've found Hill's with gradients of 10-12 degrees to be ideal and you only need 10-30m in length at most.
There are some other good starting positions that put you at good acceleration angles for sprints here.
A lot of problems can be solved if you just get stronger!
...Of course this means getting stronger in the right areas and that depends on your natural body structure.
Weak hip extensors are the most common issue amongst the population - so make sure you are including exercises like deadlift variations, powercleans, reverse hyper-extensions, good mornings, hip thrusts, glute bridges etc. in your weight training programs.
Stronger hip extensors will allow you to achieve closer to full extension off the mark, which is important to maximise your accelerating power and drive.
For video exercise instruction see this page.
Seek advice from a sprint coach
Whilst I realise this isn't an option for everyone, but there is nothing better than receiving real-time advice from a sharp eye and wise coaching mind.
You'll have to do some research yourself as to who are the best sprint coaches in your area, but don't be fooled by the latest gimmicks and training tools - many of the best sprint coaches only tool apart from their keen eye, is a stopwatch - they also won't overladen you with words and complex analysis, instead give you simple cues to focus upon.
If you can't find a sprint coach in your area and are still keen to get advice
on your sprint technique then there are online options.
There are some experienced and knowledgeable posters at Charlie Francis' forums that provide advice for no cost and like-wise other sprinting forums.
UpMyGame has provides a good free uploading service where your videos can be paused frame by frame for effective analysis.