If you are a veteran water gardener this will be old news to you, but if you are thinking about getting involved, or just went through your first year there is one thing you need to know. No matter what you do, there will be algae. Sorry, its just the way it is. And quite frankly, unless you have a well installed Ultra Violet light, algae will grow before your other pond plants are big enough to shade out the algae. There are a couple of things you must decide before you attack your algae problems.

1. Natural or Chemical
2. Ultra Violet Light

There are very good options when it comes to treatment and how to handle algae. You should decide if you wish to use beneficial bacteria and other biological treatments, or treat your water garden chemically. Pond biological boosters can help jump start your pond's ecological balance, but they are not necessary, nor always a great answer. Actually, taking a bucket of established pond water and/or a used filter mat can be as helpful to boosting your beneficial bacteria as anything you can buy. There are many options, such as Aqua-One and many of the Winston products, but make sure they are not heavy in phosphorus. This can actually make the ecology more conducive to algae blooms, it doesn't make sense, but its true. There are many other products and treatments, but these are two of my favorites.
Chemical treatments and other algae-cides are functional treatment options. They will get rid of algae for a certain amount of time, but they are a band-aid. This is also true for biological treatment, but even more so for chemical. Another warning, you can over treat your pond chemically and kill fish or plants, so make sure to read instructions carefully. For instance we had one client use a whole gallon of Aqua-One on a pond when they should have used closer to a quart. It really worked, but we wouldn't recommend this. If it had been a chemical treatment pretty much everything alive in the pond would have died. No matter which road you prefer, getting the right balance of fish, oxygenating plants, and surface plants is the best option to limit algae growth. Unfortunately the first year and early spring these factors are not established before the algae begins to bloom.
Ultra Violet Lights have not been very popular, in many areas, in the past, but these lights are quite simply the best answer for many green water issues. Any algae that travels through the UV light is killed, if the right wattage and flow is considered. Once again, read and follow direction carefully if these are not being installed by a professional. Unfortunately string or angel hair algae is attached to rock and is not affected, but another post will get deeper into that topic. UV lights are more expensive initially, but think about how often you re-apply your treatment. It may cost a good chunk of change to buy the fixture and pump, but its a one time cost, plus replacement bulbs every few years. In the long run, it really isn't that expensive.
All three of these treatment options have had excellent results from different individuals. Believe me, one is not always better than the other, each pond has different variables. Please don't be afraid to try something even if it didn't work for your friend's pond. I wish I could say "product X" will work every time in every situation, but I can't. If someone does, they're trying to sell, not help you. S0, I hope I have explained your options and illuminated what has worked best in my experience. I Good luck.