First off Welcome
Keeping the pencils sharp are aquired in a few ways, sharpeners(metal but do eat the pencil quickly), Exato knives (best option for very fine lines) , or sand paper ( shapes nicely, w/o eating the wood as well).
Next thing to note is that Pencils are just like the sticks when it comes to density. They range from soft to hard. The softer they are the better they will lay down on the paper, but this is also makes for breakage to occur more frequently.
When using sticks or pencils, you must learn to lighten your pressure you use while applying the pastel to paper. You should always start out lighter and overlay to darken, at least till you get the feel for the medium.
The Derwent are nice pencils, but I have notice that they break more then others, so you will need to work lightly till you find the perfect pencil for you.
Now for detail work, you can sharpen, and you can use blending tools. There are many threads on such, in fact I have one that has pictures of mine.
Pastel shaper/blender thread
Hopefully seeing that will lend you some ideas!
Finally, to answer the question on paper smudging! When working in pastels of any sort there is alot of dust that floats around. So you either have to work on and easel with paper upright in Vertical angle, or work on a drawing table that is angled. Since you are working in Pencils, the Drawing table would be more ideal! IF you do not have one, Try placing paper on a board of sorts and propping up one end, so that the picture angles toward you. This way you can choose the angle that suits you best and lets the dust fall away a little easier.
I use a wedge or a rolled up towel to prop my hand up from the paper, this help keeps my hand from sitting on my work. It will take some getting use too, but once you do, it will become second nature.
In the Demo threads Gaka gives a wonderful demonstration, and in there he shows how he keeps from touching his work.
I will have to find that link and send it on to you
Hope this helps!