High Voltage on PCBs: design and layout questions
The main things to consider are the required spacing around any conductors carrying high voltage, and avoiding pointy shapes on high voltage lines.

You can look at online calculators such as...

http://www.creepage.com/

...for estimated spacing between conductors.

Also consider the dielectric thickness between layers on the PWB.

For the design to be reliable obviously pick components that are rated beyond the worst cast voltages you plan to put on them.  The more margin you have the more reliable the circuit will be.