For most desktop/laptop systems, allocating a gigabyte of RAM and two CPUs to the guest VM should be sufficient.
However, when allocating space for the guest's disk, please be generous. Instead of the usual/default 8 GB suggested, I strongly recommend you make it 50 GB or even more. Of course, this implies that the host system has more disk space than this available! Also, you can specify this amount to be dynamically allocated or allocated on-demand. The hypervisor will "grow" the virtual disk optimally, not giving it the entire space to begin with.
