While I don't own any fancy, dedicated drafting tables, I do find it helpful to draw on an incline. I try to draw with the page somewhat parallel to my face (i.e. the "normal vector" of the page is point at my face). I used to draw on a non-inclined plane, but after the first time I drew on an incline, I didn't want to go back to drawing on an unmodified desk surface. I find it more comfortable to use an incline and the drawings don't get scewed by looking at the page on an "off" angle.

I create an inclined drawing surface in a few ways:

1) The Table Prop. The easiest method is to sit in a chair at the edge of a table and slide your chair back to create a little more space between you and the table than is usually comfortable (for actually doing anything at the table). Take your sketchbook (or a clipboard with some loose paper), stand it up on your lap, and lean the back of the book/board against the table. Voila! You have an inclined drawing surface free of charge. I admit this approach does encourage slouching and poor posture, but it works as a quick fix to get you an inclined drawing surface. I use it from time to time for shorter drawing sessions. Somehow even after nearly 2 years of drawing, I never thought of this method. I finally learned it while watching Glenn Vilpuu drawing in a video. It was an epic moment of realization :)

2) The Board Prop. Get a hard, rectangular board a bit bigger than the surface you will be drawing on and prop up the back end by several inches. For a board you can use a clipboard or whatever else you have handy. To prop up the back you can stack a few sturdy, hardcover books or a 2x4 piece of wood. This only gives you a slight incline, but everything helps.

3) Table-top Eisel. This is my preferred method if I'm drawing for a while and I need to use my laptop for reference images. My eisel is pretty small (about a foot wide and 2 feet tall), so I can have it on the same table as my laptop. I do get a bit frustrated by the limitations of my eisel sometimes, but I've found ways to make it work. If I really can't achieve a desired position with my eisel, I'll use one of the other methods I mention.

4) DIY Drafting Table. I've created my own table-top drafting table with a large, stiff board (I use the back side of an old white board since it's very firm and pretty smooth), a heavy box about 1/3 - 1/2 the height of the board (I just filled a cardboard box with books), and a long shoe horn (mine is metal). First, I place the shoe horn with the hooked end at the edge of a table (at which you will be drawing) with the length of the shoe horn moving away from the edge back towards the center of the table and with the hook facing upward. Then I place the heavy box on the shoe horn (on the end closest to the center of the table) to pin it down and secure it. Then I center my board on the shoe horn and rest the back of the board against the box. The hook of the shoe horn keeps the bottom of the board from sliding off the table, and the box secures the horn and supports the board. It may be a bit wobbly/unstable; so you might need to prop one side of the board up to stabalize it. Also, I screwed an upsidedown, L-shaped piece of stiff cardboard to act as a ledge for my sketchbook to rest on. Once you've figured out the materials and setup, it's pretty quick to put up, take down, move to another location, and it allows you to adjust the angle of the board by sliding the box forward or backward along the shoe horn. It does require some setup, but if you happen to have the materials at hand, you can save quite a bit of money; I use mine pretty much every day and it works rather well for me. I usually use this for longer drawing sessions when I don't need to use my laptop for getting reference (since I haven't found a logical place to put the laptop yet). If you have a tablet you can always decrease the angle of the board till the tablet will not slide off, or maybe you could even screw on a shelf to hold your tablet or phone (if I need my phone I usually just rest it on top of my sketchbook).

Method 1) is the quickest to use with no setup required; method 2) helps a bit and only takes a small amount of setup; methods 3) and 4) require more investment of money or time, but they help me to draw with good posture and a good viewing angle of the page for longer periods of time.

Of course a dedicated, professional drafting table would be wonderful, and if you have the means and the space for such a luxury, go for it; but if money and space is tight, there are other ways :) Use what you have.