Ok, now, on surface tools, and depending on the scale you using, just set the tolerance to the value that shows more of the model. Set the Steps to 0 (Patch Topology), for NO extra detail If you don't se any thing, try flipping the normals. You may get a huge change just by changing one vertex, because that may represent a change on the orientation of the spline, and therefore, changing the normals. So be keen to this. A slight change on the original may make a BIG difference on the reference. Usually solved with minor adjustments on the surface tools modifier settings. Ok, now, once your spline mesh is filled with happy polygons, all you have to do is collapse it to an editable mesh. "Oh no, editable mesh?" Yes yes, I know lots of you like editable poly. But has for me, and I like my polygons nice and counted, I prefer using editable mesh, since it gives me an accurate polygon count. I believe that Editable polygon was actually created for high polygon modeling. I'm talking, of course, aiming to a mesh smooth modification afterwards. Enough mumbo jumbo. Is it done already? Good. Let's move it on the Y-axis.
Ok, go back to the snap setting and select the "use axis constrains". This will make the vertex not snap to the absolute position of another vertex, but to the same coordinate on the currently used axis. This is good for vertexes that are on the same plane. Here comes the fun part, in case you didn't have fun before. Here you start applying depth to your model. It's easy. Just click on the Y-axis, and move around! You can also go into soft selections to get a bigger amount of vertexes moving.
Softselection are very helpful when you're starting to add depth to the model. From then on, you're on your own.
Moving in the Y axis
I usually do this for the face side. So I can get a lot of vertexes out of my way right there. Get a basic shape out of it, and now, go to the polygon surface properties, and clear all the smoothing groups. Oh yeah, nice and flat! You should always model in flat view. It's just more honest! You can really see what light will do to your model, and you can already see what set of faces will need to have the same smoothing group. Make sure you press "Q" to have that little polygon counter on the corner of the view port (this would be on the max 4 key set). But of great importance, is light!
I've already moved some vertexes, but try and keep track of your poly count as you go.
Adding lights and materials
There's this gray that I like... it's a warm gray. And it makes my model "look so good". Still I like to have black wire frame on the model. So how to do it? Easy. Make black the color of your mesh, and than create a warm gray material on the material editor. Apply it to you model and than you will have a gray shaded, black wire frame model! (Yeah, I'm losing it...)
A good material can make a great difference as to shading on the view port. It helps viewing the model's shape more accurately
Now get some lights. Make a top left yellowish light, and a bottom right bluish light. Place them a bit to the front of the model, and set their intensity to something like... 0.7. Is cool. Can you see the changes already? Look nice, doesn't it?
Two lights have been added. A top-left yellowish light and a bottom-right blue one.