Always a tricky one this, on the one hand you need the money, on the other hand your employer only has so much to go round... here are some do's

Evaluate your skills
Emphasise the added value you have brought to your job beyond the initial specification presented at interview.
Show how your productivity has increased.
Explain your contribution to the company both inside and out.
Compare the market rate via local knowledge with similar jobs in the area.
Review previous job appraisals and demonstrate areas where there have been genuine inprovements.
Remind the Employer of additional training undertaken.
Make a list of your accomplishments.

and here is one don't
Don't say you need more money because your personal circumstance have changed. Your Employer does not want to finance your yacht, children's school fees or spouses desire for expensive holidays. He simply wants to pay the going rate for the job

By emphasising the 'do's' you are telling your employer that he is getting value for money. This is a language he will understand, make yourself indispensable.

If you have given it your best shot and you still don't get the pay rise, consider the employer's position and may be relocate to an employer who appreciates you better and is willing to pay the appropriate rate for your energy, committment and skill levels..........