A couple of comments:

1. If the clothing is above water, the specular should be increased (probably size as well as strength, and lightened.
2. Underwater, there should be almost no specular on either the clothes or the model.
3. Seems don't turn transparent like the rest of the clothing. Sometimes you have great transparency maps which you can adapt. Sometimes you need to make your own. For things like cargo pants, you may need to make your own so that areas with multiple layers of cloth such as waistbands, seams, cuffs, pockets etc. don't become too transparent. Another possibility is to create a new group just for the seams (and waistband etc.) I did this for one of my early ones (the one with the woman who just walked in from the rain.)
4. Some products have great material zones. Anything by Jasmina is great. Her wedding dresses have zones for the trim, lace etc. Most of honyu's lingerie is also great, with multiple zones. This makes it a lot easier.
5. Use transparency maps. If the clothing already has one (for example, a lot of lingerie, or stockings does), take the transparency map, plug it into an exponent math node, and raise it to a power. This will keep the light (opaque) parts light, but the already transparent parts will become more transparent. This is especially nice on stockings and lace. The input from the map itself may be at 1, or slightly less, or even more. You can also invert textures for transparency. For example, suppose you have a white dress with a darker flower pattern. Plug it into a math node where you subtract the texture from zero and it will invert it, making the white part transparent and the flowers less so. Possibly run this into an exponent node, and then into the transparency node.
6. if the clothing isn't really close fitting on the breasts, shoulders, and hips, you probably don't want to make it too transparent. The gap just doesn't work. You can do this if the figure is under water where the fabric might float.
7. Dynamic cloth works really well, but there are a couple of things to keep in mind. First, you want to increase the stretchyness and density. Second, if there are constrained groups, you still might get "gapping", but you might try making those groups unconstrained. Finally, sometimes conforming clothes (like harry-cn's leotards) work well when made dynamic. (I'm slowly working on something using these.)

You might look at my gallery for some examples.