Project Startup

Name. Think twice. Sleep Over. Think twice again.
Confluence Space, to document what is or shall be
Jira Project, to plan and track actual progress
Jira referencing Confluence is better than vice-versa
Plan and Document Architecture, Features, Roadmap ... in Confluence
Create a Jira issue for each and every task, beginning with an Epic as top-level task

Documentation principles

Document intentions before you plan your architecture or implement anything
Document architecture before you implement
Create a Jira task before you implement
Write the interfaces before the implementation
Commit small, but ...
- in the commit comment, describe what you have done and why you have done it (issue numbers help)
- try not to break builds. If you break a build, warn every possible co-developer
Document classes and methods in the interface, not in the implementation
When resolving Jira issues, document the svn revision numbers in the resolution comment
Before closing Jira issues:
- test the solution and write an according comment
- compare the result with the intentions, document differences
- if necessary don't hesitate to create follow-up issues for unresolved details or new ideas
Document successful mechanisms or strategies not only in the project space but also as Best Practice space and/or technology space
After creating or extending a library, write a HowTo that allows other developers to pick it up without studying all your code. Test cases and HelloWorld programs often are good source examples, if others are able to understand and run them out of the box.

Try hard to inlcude details in error messages, i.e. point to the content (FIXME bad and good examples)

Spaces are better than tabs, because only spaces have an exact width stable over all the editors out there