Do I just leave some space not partitioned and thats all?
First, a SSD works totally differently compared with a HDD. On latter you actually assigned physical disk space (cylinders) to partitions. On SSDs partitions are purely logical, the space actually used for storage is distributed by the internal controller, which takes wear leveling into account, among others.
SSD manufacturers usually already overprovision their devices in the firmware. You may increase that by leaving some (logical) space unpartitioned, so the controller has more free capacity to work with. Or you can create an unused partition which you label accordingly to make clear what you intended.
But speaking from my (limited) knowledge, for the usual use cases (typical workstation use, not too write intensive) you could just assign all available space to partitions, and take care that the total space you use (over all partitions) doesn't exceed a certain percentage. So you make the best use of the capacity you paid for, without needing to repartition later (at least if your partition schema was sufficiently appropriate for your use), which would be a very write intensive process.