Please start with learning proper terminology. What is "IT-Software", for example?
By all features you mentioned, this is nothing more then project management software. But I would prefer such software integrated with Revision Control Software, Issue Tracking, Developer's Wiki, and the like.
First and foremost, look at existing software of this class, first of all, open-source. And then think about this: do you really need to develop your own software? Who will use it? Are you going to introduce something essentially new? Are you going to offer some essential improvements to the features of such software?
Also thing about this: To introduce such innovations, you would need to have some good ideas. But you are asking about the ideas. Now, do you think someone will give you some ideas which would be really innovating and would even give you some competitive edge? Well, this is possible. But it's even more likely that a person having such idea will try to use them without sharing with you, at least not until those ideas will be already implemented. Only a person having good ideas but having no time for using them could give you some; that's why I said it would be possible.
If you are determined enough, look here:
http://en.wikipedia.org/wiki/Software_project_management[
^],
http://en.wikipedia.org/wiki/Project_management_software[
^].
Learn some books and articles on software project management "theories". I put this work in quotation makes because I have some good reasons to consider such "theoretical" work as pseudo-science, almost like alchemy. Nevertheless, some of such people share interesting real experience which is good to study.
I don't want to discourage you. Just the opposite: if you have interesting and helpful ideas, don't hesitate to start, better with some working prototypes.
One my idea is: exchange ideas with your fellow software developers. Learn what would help them in their work. I notices long time ago: best software it the software created for yourself or your friends or relatives.
—SA
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