Using Voyant Tools
A free, open source, and useful text analysis software is Voyant Tools.
For a full list of Voyant tools, see the Voyant Tools Index.
Below are a few Voyant tools that you may find useful (with screen shot examples).
Corpus Type Frequencies Grid orders the frequencies for the terms in a corpus.
For looking more closely at the context of a particular term, Document Type KWICs Grid lists the phrase immediately preceding and following a word or word root identified by the user.
For a graphic depiction of the distribution of selected terms across a corpus, try Type Frequencies Chart.