[mothered]

Definitely a firewall and to help avoid traffic monitoring and capturing, hard code your connection via cable/ethernet.

Dedicate your systems to specific tasks, such as one PC for sensitive account logins, another for general navigation and so forth. Run virtualization software (VMs) and In the absence of a VM, run all files and applications In a sandbox environment. To help protect against viruses and the like, boot off a Live CD. Also, of significant Importance, always exercise common sense and good judgement. There's heaps, I've only named the basics.