I would recommend trying to keep the level of your Headquarters, equal to your Manager Level (if financially possible).
The order of importance for Headquarters is often debated between managers, and can change as you level up, but for a manager of your level, I would suggest:
1. Technology (Boost and DRS) [Most Important]
2. Design
3. Manufacturing
4. Simulator
5. Youth Academy
6. Offices and Hospitality [Least Important]
* This is just my opinion and it is likely that somebody else will rank the HQs in a different order. *
As you progress towards Level 30, manufacturing may become less important and YA and O+H will work their way up the hierarchy but overall, trying to match your HQ level and manager level is a decent strategy.
I hope this helps you - if you need any further assistance, feel free to ask.
