Which helps the developers

I am a developper since a long time. Down, you will find some point that I find important.
Click on a point to have the explanation.

The more legible a code is, the easier it will be understood by everyone.
Some languages have powerful syntaxes but this kind of syntax makes the code difficult to read for everyone.
Try not to write too long lines, to give variable names that easily identify the content.

It is important to explain what the code do.
You (and the others) will appreciate it when you will come back in the code. Sometime the operations which the code do are more or less complex. It is very usefull to comment it before, to explain simply what it do. Don't forget to adapt the comment when you modify the operations.

Your devs must have a good structure if you want it would be evolutive.
Try to re-use code with creating function (or library of functions), use Object-oriented programming is very usefull. Never repeats code.

Never say : I will fix it later.
When you have a bug, fix it immediately. The correction may have an impact on other parts of the development. Be careful with copy / paste.

If you think test-first is expensive, try debug-later.
It is important to test everything when modifying a function. This change may have an unintended impact on other components.

We work on computer but we are not a computer.
Stay in good ealth.

First, the program has to do what it has to do.
There are functionalities in development tools that can identify time-consuming treatments. It is better to improve a treatment, called many times, which takes little time, than to modify a longer treatment that is called only a few times.

Even though this changes throughout the development process it sets the scene for the entire project and how it will be implemented.

The client doesn't know exactly what he wants.
When he saw the result, he ask modifications, he thinks of things. But too many modifications cost a lot.