There are 3 types of clothing:

Dynamic:  This is clothing that you use inside the Cloth room. It takes longer to work with and there is a bit of a learning curve, but it's not too bad, but the results are more appealing in that the clothing actually looks more natural instead of "posed and stiff".  I have included information about this type of clothing further down.

Confroming- Non Morphing:  This is clothing that you conform to a figure. The clothing is made to fit the base figure.  If you change the shape of the figure you will also have to refit the clothing, which isn't always easy if there aren't any corresponding body morphs in the clothing.  Plus posing a character in positions where they are not nearly upright is difficult.  But many prefer this type of clothing over dynamic.

Conforming-Morphing: This is the same as conforming-non morphing, only there are morph dials that you can turn that have corresponding body morphs for easier fitting.  This is the preferred type of conforming clothing because it's easier to fit. To fit this type of clothing, select the body part of the outfit IE: hip, thigh, chest, arm, collar etc, and look in the parameter dials for morph dials that you can change to help fit the clothing.  Unfortunately sometimes even with morph dials, if you have morphed the figure a great deal, it's still not very easy to fit the clothing.

Using a clothing item on a figure that it is meant to be used on, after you have added morphs and adjusted the shape of the body,  can be problematic because the clothes are made for the default figure shape and not the new morphed up shape. So the clothing no longer fits and you get parts of the body showing through the clothing after you add morphs and change the shape of the body.

There are programs that can help fit clothing from one figure to another, or even from the same figure to one that has been "morphed up" using their morph packages.

The Tailor, which can be bought here:
http://www.daz3d.com/i.x/shop/itemdetails/-/?item=3679&_m=d

Wardrobe Wizard (I use this one and it's great). It can be purchased from PhilC's site here:
http://www.philc.net/WardrobeWizard.htm

Clothes Converter, which can be bought here:
http://www.daz3d.com/shop.php?op=itemdetails&item=3069&cat=131

There is also another one, I think by EvilInnocence, called "Cross Dresser". 
http://www.evilinnocence.com/xd/

Dynamic Clothing (more information):

A nice thing about dynamic clothing is that you can easily use clothing on various figures.Here are some tutorials on how to use dynamic clothing in the cloth room:

http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2665209

http://www.philc.net/CC_sampleVideo.htm

http://www.poserfashion.net/howvic3dress1.htm

http://drgeep.com/p5/cr/cr.htm

Here are some links to some great FREE dynamic clothing:

http://www.renderosity.com/mod/freestuff/index.php?username=mapps

http://www.renderosity.com/mod/freestuff/index.php?username=svdl

http://www.renderosity.com/mod/freestuff/index.php?username=Stegy

http://www.renderosity.com/mod/freestuff/index.php?username=carib98

http://www.renderosity.com/mod/freestuff/index.php?username=teyikung

It's also possible to make conforming clothing into dynamic clothing:

http://www.renderosity.com/mod/tutorial/index.php?tutorial_id=868

And it's possible to take a conforming outfit and work with it in the cloth room so that parts of it act dynamic.

http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2517340&page=1

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi