If you ask a specific question, like "I'm willing to do X, will that make me more secure?", then you can get a specific answer. When you ask an open ended question like, "What can I do to be most secure?", you will most likely get answers (from me, at least ), that you are unwilling to implement. For example, to be most secure, you should configure an anonymizing middle box. This would be a PC in a nettop or HTPC form factor with 2 network interface cards, running OpenBSD, which transparently proxies all connections from your main computer over Tor. Tails already transproxies all connections over Tor, but it can theoretically be rooted and the attacker can simply remove the iptables rules, shut down Tor, etc. With the transproxy on a separate physical box, you are much more secure, but are you willing to invest a couple hundred dollars in the hardware, as well as the time required to learn how to properly configure it? Probably not.