Well, how many plants do you have in your tank?? Usually it is better to have more plants than less, as the plants then out compete the algea for nutrients. What are your nitrates at? High nitrates can sometimes contribute to algea as well. Usually though, algea is caused by excess nutrients in the water. You can combat this by planting more plants, and feeding your fish sparingly.
There are several ways to fight the algea you already have. Do a few frequent small water changes. Cut the lights off for a few days, wrapping the tank in paper to keep all light out. But I think most important is to plant your tank very heavily with fast growing plants that take their nutrients from the water so that they remove any nutrients the algea might use to grow. I have pennywort in my tank, they have roots at every leaf that hangs out in the water and sucks up excess nitrates, etc. Do a search for algea control, I am sure you will find more plants than this, I just can't think of anymore right now.
I think though, the recommendation is that if you are going to plant your tank, to plant about 75% of the bottom, to outcompete alge, with fast growing plants right from the start. Then, once your algea disappears you can replace the fast growing plants with plants you like better.
Hope that helps, and if anyone else knows of something different, please post. This is all I can think of right now, as I haven't had my coffee yet.
Jan