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It is one of the most pervasive misunderstandings in computing that the source code is for the computer's consumption. Computers work with low-level binary code, a series of impenetrable 1's and 0's or hexadecimal numbers, not the structured high level languages we code in. The reason that these languages were developed was to help the programmer.
In practice, coding for human consumption means coding for clarity first, over efficiency and speed second.
The comment is the extreme example of a language element for human consumption. Most compilers will strip the comments from the executable program. The purpose of the comment is to tell you (and any future developer) what the program is intended to do. Write comments with this in mind - and avoid simply restating the code.
Good comment: Calculate the gross asset value adjustment Bad comment: Set cmd Enabled = False
A good indication that you have got the level of comment right: could someone understand what your program is intended to do if all but the comments were removed?
Just as it is important for an author to split a book into chapters and paragraphs that aid reading so it is important for the developer to consider the layout of the code and how that can aid readability of the code. In particular any code branch (an IF..THEN...ELSE construction) and any code repetition (a WHILE...END WHILE construction) should be indented so that it is easy to see where they start and end.
Before you open a file, make sure that the file is present. Before you set focus to a control, make sure that the control is visible and enabled. Try to work out what conditions could cause your code to fail and test for them before they cause the program to fall over, and do not rely on error handling to .
There are a number of strategies to variable naming. The key is to be consistent
and to be as informative as possible. If you name a variable MonthNumber, you give
the programmer extra information as to what that variable is expected to
contain. I personally prefer the Hungarian notation style
I am convinced by the arguments that hungarian notation is harmful for readability - but
whichever style you use, consistency is the key.
A function or subroutine should ideally only do one thing. One of the greatest sources of misunderstandings, in my experience, is a subroutine that does a number of different operations. This should be split into separate functions for each different thing it is doing so that these in turn are easy to reuse, and the scope of a code change is easy to understand.
Functions and variables that are only used in one module should not be visible outside that module. Variables that are only used in a function or subroutine should not be visible outside that function or subroutine. This prevents any use of a variable or function outside of where it makes sense to use it.
When I originally wrote this list about five years ago there were only seven secrets, but more recently the article was referenced on a couple of programming blogs and as a result I got a lot of feedback. As such I have clarified some of the points and struck out the bits that I no longer follow.
So the eigth secret is to keep an eye out for new opinions and methodologies and to evaluate them in an impartial and rational way. This applies to your choice of language, operating system, back end database and development methodology.
There are many other hints and tips which can help you become a better programmer, which will make you more efficient and the programs you write more maintainable, but the eight secrets listed above will serve as a good foundation - however high you build upon them.