I’d say that you need to reality check a minimum of eight times per day. However, quality counts as much as quantity with reality checks. If you begin to ask yourself “Am I dreaming?” and then automatically reply “Well, no, obviously not,” and then move on with your day, the checks probably won’t be effective later on.
Each time you check, spend a full twenty seconds or so really investigating the nature of your reality. (You might try asking yourself: What was I just doing? Can I remember my name? Can I do simple math? What’s 9x7? Can I fly? Is anything strange or different?)
I’ve tried reality checks in dreams before and have been fooled! I’ve asked myself, “Wait, am I dreaming?” and then have rationalized my way out of lucidity with arguments like this: “But the sunlight feels so real on my skin”; “Hmmm, I must have dyed my hair another color and have forgotten about it”; etc.
The drawback with my suggestion above (using a dream sign to become lucid) is that lucidity is then dependent on you having a dream with that dream sign in it. Dream signs are still worth noting and meditating on, but the best reality checks are centered on ordinary events that you’re very likely to dream about.
Ryan Hurd (author of “Lucid Immersion”) recommends reality-checking every time you pass through a doorway. I’m just trying this out. I haven’t become lucid with it yet, but I think it has potential. Basically, whenever I pass from outside to in, or inside to outside, through a doorway, I say “Threshold” and pull myself out of any other thoughts and investigate my reality.
So build reality-checks around things you do all the time, like passing through a door to the outside, sitting in a classroom (if you’re still in school), etc.
To be honest, I often go lucid simply by noticing strangeness, but I have had success many times with looking for my hands in a dream. If you haven’t heard of that technique, basically, in a nutshell, you tell yourself that you’ll look at your hands in a dream and then ask yourself if you’re dreaming. Throughout the day you look at your hands and perform a reality check. It’s very reliable because your hands will always be there in a dream (well, almost always).
I’ve found that going lucid within the dream is 90% dependent upon the frame of mind I fall asleep with. I’d describe the ideal mindset as having these qualities: carefreeness, optimism, a spirit of fun, a persistent but gentle focus on staying consciously aware as long as possible before sleep. Ideally, there’s a period of fifteen minutes or so of “fun struggle” to stay aware as I fall asleep and then, at that point, I let my mind freely wander and I give up trying, but still ride the feelings of carefreeness/optimism/intrigue into sleep.
Don’t underestimate the power of your mindset, and emotional resonance, right before you fall asleep. They can easily carry over into your sleep and dreams.