The best way to protect your VPS is by enabling/installing the firewall.
On a
Windows VPS, make sure the default firewall is enabled and un wanted ports are removed. Apart from this a good anti virus is an added advantage.
On a
Linux VPS, consider configuring csf OR configuring iptables. With csf firewall, you will be able to open the required ports (incoming as well as outgoing). You can block IP's with syn flood OR time wait states.
Depending on the nature of attack, you can optimize the firewall rules as required.
What platform do you use & was your VPS affected with any such attack ?