I like it when I observe my thoughts and realise I am not really thinking them, I am not my thoughts I am the peaceful, detached observer of them.
I sometimes close my eyes and sometimes leave them open, I usually find concentrating on my breathing is the best way to start.
Alera, I always thought of mindfulness as a state of mind to be in as much as possible? Like being 'present'. Often I don't meditate as such but try to be 'present'.