Anyone here has any idea what is the best character to start with or there is no such rules? Please comments. thanks
that's clearly no such rules. That's all depend on how will you use your domain. If you want to use it by your own then use domain name that impress your site. If you want to sell it immediately then just go check market needs. I heard the great domain name consist of balanced vocal and consonant e.g. sedo.com, kekida.com, or any other like that. That should be worth thousand of dollars.
@honestloez: the guy above you is a spammer. Alvin, there are no such rules. Just use the keyword of the niche you are doing, add another cool word to go with it if it's not available OR start a brandable domain name(LLLL, LLLLL or LLLLLL), then you are good to go.