Awareness is an absolutely must. Without awareness, you probably wouldn't realise that you should reality check. The problem about the relation of waking life and dreaming and i'm sure you've heard this, is that what we do in waking life is reflected within our dreams. This, likewise goes for reality checks. If you do not question your reality, question that 'this could possibly be a dream,' your reality checks just won't happen. Because we accept our reality in waking life, we do the same for dreams.
As for the dream journal, you can try and dream journal consistently with as much detail as you can remember within your dreams i.e. lighting, room colour (everything) and try to pick our recurring elements of your dreams, dream signs. Once you recognise your dream signs, question your reality whenever you see them in waking life.