Google Nexus 7 does not have microSD card slot. Adding extra SD card to increase storage space is not an option. You will face low disk space issue sooner or later especially for those with 8GB storage model (like mine). My Amazon Kindle Fire serves me well even with 8GB storage only. However, situation is not the same with Nexus 7 because it supports lot of interesting Android games with NVIDIA Tegra 3 GPU. And most of these advanced 3D games require lot of disk space. Luckily, I manage to put most of my music, photo and video on external storage like USB flash drive. And connect it with USB OTG cable when needed. Of course, with the help of StickMount application too. Note – root access is required.
