First I am just a forum member, but here are my thoughts.

Some people just have oily scalps, but if you are using a shampoo that is stripping away too much of the natural oils your scalp produces then the scalp produces ever more oils and so a vicious cycle that never seems to end happens. I would suggest trying a shampoo that is supposed to 'normalize' your scalp. It sounds odd, but Matrix Biolage makes one and my husband has used it with great success. His scalp is much less oily now that it was before he began to use this shampoo. He is on his 3rd or 4th bottle now.

My own scalp is lots less oily since I stopped shampooing so much. I clean my scalp every day with no silicone conditioner and shampoo every third day with a no sulfate shampoo. Turns out my scalp just hates sulfates and rebels when sulfates are used on it. Because I don't use sulfates I also don't use any silicones that are not water soluble.

Hope that helps!

I don't think there is any way to make your hair less oily.  I would just wash it as often as it needs.  I personally cannot get by with washing every other day, so I wash every morning or else I look greasy.  The brains have a slightly confusing post on this topic http://thebeautybrains.com/2010/01/28/can-you-train-your-hair-to-be-less-oily/  But you have to read their bottom line.  If you shampoo less often, your hair WILL slow down oil production, but you'll still have the same amount on your scalp as if you shampooed daily (i.e., the scalp only slows down oil production once it detects that it has reached its chosen level of greasiness, kind of like its greasiness "set point").  The scalp won't be less oily overall.  A good analogy might be if you have an overflow drain on your bath.  The water level will reach a certain level before the overflow drain kicks in and keeps it from rising any further.  But it will always rise to that level before the overflow drain takes any water out, and it will only take out as much water as it takes to get it back down to the level of the overflow drain.  Some people just have oilier scalps than others.  Use lightweight conditioning products, and use a shampoo that thoroughly cleanses.  That's my two pennies.
P.S.  The good news is that if you're young, you may get less oily overall as you age.  And then you'll be glad because all of your aging buddies will be too dry...Also, ask for a reference on that statement that oily hair causes hair loss.  I'm no expert, but that sounds fishy to me...

Everyone is different.  I've never succeeded in doing that, but on the other hand, I have fine hair so it looks bizarre by morning anyway (just from lying on the pillow, let's just say it takes a whole new shape), and shampooing serves to refresh it.  My guess is that people with thicker or curlier hair can get away with less washing more easily than fine hair.

So I found this on the minoxidil site.  http://www.minoxidil.com/subpages/hairloss_myths/hairloss_myths_catagory_a.html#a07  Not sure what their sources are, I couldn't find a scientific source on whether oiliness causes hair loss.  I can only say that I have had fairly oily hair all my life and always had plenty of it.