If you're finished cycling, and you're sure of this--no ammonia, no nitrites, and nitrates are beginning to accumulate, then it's time for a water change. Are you using RO/DI water? If not, consider getting an RO/DI unit. Are your lights in need of changing? There are many contributing factors to algae, but most are attributable to nutrients in the water on which nuisance alga thrive.
The trick is to not provide the algae with sustenance. Get rid of nitrates for starters with a water change. If phosphates are present (if you're using tap water, they probably are), consider a
Phophate Reactor which can be had for less than $50.
If you don't have a refugium, maybe start one up with a ball of chaetomorpha, and a daylight type lamp, burning when the day's over and the tank lights are out. This chaeto will compete with tank algae for nutrients, and if you play your cards right; the tank nuisance algae will lose the battle.
You have a long road ahead of you, but if you ask questions and take the advice of the many experienced folks on this site, you can't lose!
Good luck, Polly!
One last thing, why not draw up a signature with all pertinent tank specs, so those who respond to your questions will have some information and not have to ask so many questions of you.