Since I waste lot of time on interpreting bug reports, I'd like to give a little guidance on how to file it correctly. I would claim that I spend at least 10% of my time on guessing and asking the reporter what the bug means. Plus - 5% more on fixing stuff, that I thought I've already fixed but misinterpreted the ticket because it was to vague or badly written. That is 15% completely wasted time.

Explaining "the issue"

A simple "does not work", does indeed simply not work. You should try to use at least three interrogatives like: what, when and where.

It is also important in some situations and especially for web development to mention the browser or device and the version of it, the operating system, the screen resolution, etc.

Be precise in your description to make it reproducible.

Use screenshots

If something is hard to explain with words - use screenshots if possible - or show it on screen to the developer.

Prioritizing

Try to prioritize the bugs. Or even better, let the developers estimate the bug's and then prioritize it.

Evaluation

When the developer said it should work now, for instance he/she has fixed a color, or behavior - you should always clear the cache before you try it out.

An analogy

Do you remember math tests at school? The teacher always marks the error preferably with red. The teacher did also note what exactly was wrong: Sometimes only the result was wrong, or you missed a comma, or used the wrong formula.

Imagine the teacher would only mark the whole arithmetic problem as false or even worse, just write a big nasty failed under the test and leave the rest to you ;)