Backup your data. That's something that's repeated over and over and yet too many people don't really take it to heart. If you've lost data in the past, I be that you're backing up now like it's a religion. If you're not backing up, maybe you've never lost any data or maybe it's just something that you haven't gotten around to yet.
If you're on one of our VPS plans, you have a measure of safety in that we do perform full filesystem backups of those server images on a weekly basis. We rotate those and keep the previous 2 on hand should you need to either revert fully or just grab a bit of data (you can do this from your control panel). This also applies if you've opted for our 'vps on dedicated server' setup.
That may not be often enough depending on your specific circumstances though. If you have a highly dynamic site that sees changes all though the day, you likely need to implement more frequent backups. That's something we can definitely assist with. Just pop in a support ticket and let us know what your requirements and we can help by putting your data in a safe place and your mind at ease.