DOF with 55-300mm Nikkor lens?

Is it possible for me to take DOF pictures using 55-300mm Nikkor lens…
i'm a beginner…

Sure. Put your subject close and the background far away. Use f/3.5. Shoot. There you go.

Sample, even if only at 200mm:

Here's a bunch. Read the captions.

Depth of Field (DOF) is defined as that area in front of and behind your subject that is in focus. It can be very shallow or very deep or anywhere in between those extremes. There are only three factors that affect your DOF:

1) The focal length of the lens.
2) The f-stop (aka aperture) used.
3) The subject distance.

At http://www.dofmaster.com/dofjs.html you can learn about DOF and how to control it. You can then use the DOF Calculator to compute your DOF for any combination of the three factors imaginable.

Since the close-focusing distance of your 55-300mm f4.5-5.6 lens is about 4'-7'' lets look at a couple of examples with our subject at 5'-0''.

55mm @ f4.5 focused on a subject at 5'0'' your DOF is from 4'-10'' to 5'-3''. Anything from 0'-2'' in front of your subject to anything 0'-3'' behind your subject will be in focus.

300mm @ f5.6 focused on a subject at 5'-0'' your DOF is from 4'-11-7/8'' to 5'-0-1/8''. Anything from 1/8'' in front of your subject to anything 1/8'' behind your subject will be in focus. 1/4'' total DOF is close to zero DOF.

You can play around with the DOF Calculator and check the DOF at every available aperture on your 55-300mm zoom at any subject distance and focal length you choose.

One last example:

300mm @ f11 focused on a subject at 100'-0'' your DOF will be from 92'-11'' to 108'-2''. Anything from 7'-1'' in front of your subject to anything 8'-2'' behind your subject will be in focus.

If you mean 'selective focus' shots where the subject is sharp and the background blurred then yes you can.

Get as close as you can to the subject and use the widest aperture (lowest f number) you have, this will minimize the width of the DOF.

Focal length is often quoted as a varable, the only thing that focal length of the lens alters is the subject to camera distance, nothing more. If you fill the viewfinder with say a persons head, you will have to be closer to the head at the 55mm end of the zoom, at the 300mm end you will be further away, if you frame the head exactly the same, the depth of field will be exactly the same.