Be sensitive to the timing. If your boss is in a great mood, go for it. If not, wait. Most companies have a salary range structure for each position. Find out what your job's salary range is and where you fall in that range.
Salary ranges usually overlap between junior and senior positions.
You may need a promotion to get the compensation you deserve. If you must obtain a promotion to get your desired salary, find out what you need to do, or if an exception would be made in your case. The amount of a salary increase usually is based on where you fall in the market comparison, along with your significant contributions to the bottom line of the company. Another factor many managers consider is how you perform your duties compared with other people on the staff with similar technical responsibilities, and what they are being compensated. Be prepared for your manager to think it over, review the information you have provided, get approval and get back to you.