+ Question authority. Don’t assume your boss/lead/manager always knows the best way. If you have a better idea, speak up. But don’t take it personally if your idea isn’t used.
+ Don’t start until you understand how your task/role/code fits in the big picture. All too often, I have seen developers build something that isn’t quite right because they didn’t make the effort to understand the world around them.
+ Your code is broken until proven working. Don’t submit untested code even when you are in a hurry. It will slow down QA, who has to find and document your bug. It slows you down because you have to go through your bug reports, open your code, remember what is going on in there, fix the bug, test the bug, and resubmit your code. It will make your project later than if you had taken the time to do it right the first time. If you need more time, talk to your boss/lead/manager.
P.S. submitting bugs is bad for your reputation too.