The first thing is avoiding physical ones such as friends who can enter or access your computer without you noticing them, they are the first you need to watch out for so password your whole computer. Secondly check carefully what you are downloading and links clicking on. Also have a trusted anti virus and paid for it to secure your computer.
The key word friend attracted me; keeping many friends is harmful to your computer or phones especially when you are a successful crypto trader
And from experience; you need to watch your pass phrase around friends