Those of you who intend to record your own samples will need a
stereo mic. If you don't have one you can always set up two mics to
capture a stereo sample. Back in the studio, when editing samples, you
might decide that either the left side or the right side or both are
keepers. Remember you always should do at least two takes of all your
samples. This increases your odds of getting a better sample.
Take your time to make your samples the best and most unique quality you can. When you have a good library you will not only be able to embed them into your projects but you can make them commercially available to make some extra money.
If you are a guitarist you can go through all the major and minor keys and record all the fundamental progressions, for example 1,4,5 - 2,5,1 or the circle of fifths, with different inversions, articulations and sounds. Then when you are writing a song you can import those individual samples and construct a composition.
You can also make different arrangements of your samples and use them to improvise. By doing this you will increase your ability to be spontaneous. This is time consuming, up front, because you have to record many progressions in many different keys with many different sounds, but then you'll find yourself writing music is a new way.
You can do this with piano or drums; build a library, and write with it.