Inception, to put simply, is not possible. Seeing as we currently cannot connect dreams together with two people being able to interact with eachother
At the risk of sounding crazy, this concept is called "mutual dreaming" or "shared dreaming" and I have attempted and achieved to some level a shared dream. While its not scientifically accepted, two others I knew who I saw in the dream recalled it before I did. I will elaborate if you are interested.
To lucid dream, you must first be able to remember the dreams you have or else you will never know if your dreams are lucid or not.
Dream recall does not prevent lucidity, its just better to ensure you have good enough recall to be able to remember most of your dreams so no efforts go to waste.
Once you can remember your dreams, becoming aware is the second most difficult part. Steps like counting footsteps as you dream or remembering a song lyric and repeating it over and over again in your head will aid in causing you to become aware.
"Reality checks" or "RCs" are important, but the ones you have listed are hideously poor. More common RCs are counting your fingers (an uneven number of fingers is an obvious sign) looking at an brown townog clock twice or a digital clock once (skipping of time or morphed imagery are common with these) or even simpler, plugging your nose and trying to breathe. RCing must be practiced throughout the day, so when you are asleep you do it naturally.
Once you are aware you are dreaming, your subconcious has already constructed the world around you in the dream, and you will be able to change and modify anything you want. For example, the scene in Inception where Ariadne takes half of Paris and puts it face-down on top of the other half, is completely possible.
Very truce, I saw the trailer of the movie and have accomplished the face-down thing. Except in my dream I watched the earth fold over and then I jumped into the flipped version and I got sucked into a parallel world LOL.
The last step is being able to stay sleeping. a "Kick" is simply either A) when something occurs physically outside the dream in real life such as tipping over in a chair, falling into water or being slapped in the face, or B) inside the dream, when you are killed, fall down a huge distance, or something like that.
Again these are crap examples hurp. To stay in a dream or to make it more "vivid" you should either touch your own arms or hands (the sensation really hits you in the face and sinks you into the dream) or spin around. Falling or death generally results in waking up.
Waking up may accidentally occur when you're in a dream because you've done something wrong and accidentally "Kicked" yourself (died, derp). After huge amounts of self training with lucid dreaming you should naturally be able to stay in the dream without kicking yourself.
Even the most experienced wake up. You can only stretch a dream so long before your sleep or REM cycle dictates otherwise. If you do wake up, train yourself to NOT MOVE so you can fall back into the dream. Your brain won't realize you are awake and it can take a matter of seconds to be asleep again. This technique is sometimes referred to as "DEILD" which stands for dream exit induced lucid dream.
If you manage to start lucid dreaming I highly suggest you stay on the first layer, and only go to a second layer if you're heavily trained.
Are you kidding me? False awakenings are all part of the experience, nobody goes "insane". You'll just wake up with intrigue, there is no danger.
I myself have been lucid dreaming randomly for life, but only since late 2008 have been practicing it as a hobby. I've had hundreds of lucid dreams, I get a few each week if I can be bothered (sometimes you are just so tired its not worth keeping mentally prepared). I recommend you keep a dream journal and write down dreams in diary format, helps your recall.
