Read the Manual

A great deal of the time, software developers can mostly figure things out by just trying things, and seeing what fits.  Maybe it's a matter of trying different combinations until the compile error disappears, or maybe it's a matter of searching online until a snippet looks like it might work.  In any case, although trial-and-error can certainly produce working software (and some great stories and some knowledge), sometimes actually reading the documentation, manual, or instructions is warranted.

Quotes

When all else fails, read the instructions.

References

RTFM on Wikipedia

2013 Software Craftsmanship Wall Calendar