Do not miss the other important topics of IT construction: documentation and testing and debugging. Documentation is an ongoing task in all development phases. Testing and debugging has to be done on different levels: modules, programs, subsystems, system.
First and foremost you should have good programmers around in order to be able to create good quality systems.
For testing I have created an Excel © application which provides test data of different data types and with specified statistical features.
One important part of IT quality is data integrity and consistency.
If delivering a software make sure that your customer will receive official notification about delivery date, necessary training and first week/month support. If you have to make 3 or more emergency changes on your software within the first week of production you definitely developed poor quality.
A small documentation example is presented here.
A somewhat exotic but nevertheless important aspect of IT quality is a solution approach which is
a) efficient (in terms of runtime, storage usage, etc.) and
b) manageable (in terms of complexity and maintainability).
For Excel © array formulas - sometimes also called matrix formulas - I postulate my w-rule of IT quality here.