Hard money is education's bread and butter provided by local property taxes, state aid, state and federal entitlements, bonding, fees, etc. Access to hard money is closely controlled by state lawmakers. It is relatively stable, but subject to state booms and busts. Hard money is for doing good. Soft money is for change - for doing better.
Soft money is for devising ways to get better results with hard money after the grant period.
Projects that permanently change the learning environment and impact many students. Collaborative projects with business partners, parents, community groups, student involvement, etc. Projects that can be self-sustaining after the grant period ends. Yes, you can get grants for hardware and software, but your goals and student learning are what is important to the funder. General school operating expenses, including salaries.