Photography is a business. Treat it that way.
The very first step is being honest with yourself. Is your work professional? Is it as good as your competitors? If you think it is, then ask your friends and family, then ask your competitors. If everybody thinks you're good enough, have at it.
the next step is to see what your competitions is charging. Don't undervalue the market or you do yourself and your competitors all a disservice. Don't overcharge or you won't last very long.
Once you see what they are charging, figure out your bottom line. Your break even rate. Include all the photography equipment, factor in upgrades every 12-18 months and don't forget computer equipment, software, and storage. Include insurance, car payments, rent, groceries, gas, repairs, marketing materials including a website and advertising, etc. Once you have a solid number of how much money you need to survive per year, decide how many days per year you plan to work. You unfortunately can't include non-billable days such as building your website or updating your portfolio. Divide the first number by the second number and you have a daily minimum for your work. Charge under that number and you're losing money.
That's the basics. Want to learn more? Take a business class at your local community college. or seven.
Bottom line, the more irresponsible you are about your photography, the more professionals in your area will suffer.