I'll talk a little bit about style in technical documentation, since I have a bit of experience. The important thing is to explain as clearly and simply as possible.
Let's say you are speaking about a cursor in a recordset, and you wish to do one thing (we'll call that thing X) if you are on the first row, and another thing (we'll call this one Y) if you are on any other row. You might say this:
If the current row is the first row of the recordset, do X. If the current row is the second or subsequent row, do Y.
I wouldn't say "If the current row of the recordset has a predecessor, do Y, otherwise do X." This is perfectly clear, but it is less simple, because it requires the reader to reason out that only the first row does not have a predecessor, and also that otherwise in this case refers to the first row. While it might not be difficult for your audience to do this, it still requires more brain overhead than my example.
Another thing that requires brain overhead is the use of pronouns, because the mind has to allocate memory space to what the pronoun refers to. So, you will note that I have repeated "current row" in the second sentence, rather than saying "it".
So, your primary goal is to communicate the idea while requiring as little of the reader's effort as possible to make the idea understood. Setting combined secondary goals of clarity and simplicity will help you to accomplish this. Keep in mind that clarity and simplicity are often contradictory, because if you oversimplify you lose clarity, and if you overexplain you lose simplicity. Work on striking a balance between the two.
[Edit] In my example, I removed "any other row" in favor of FumbleFingers's "second and subsequent row". In part, it is a bit more precise, since it requires a bit of brain overhead to realize that "any other row" means the second row and all rows thereafter. Also, it is as he says a standard phrase. Another part of accomplishing the goal of requiring as little effort as possible on the part of the reader is to use phrases that are already well understood to mean specific things in your technical area of expertise.