First off you need to understand the difference between the hardware and software. Apple is a company while android is a software. If your just building the hardware you will probably just run android on your phone, but if your making custom software too you will need years of experience with programming.
Secondly you need a pull. You need people who are willing to buy your product so you dont have a crash from no sales.
Third you need manufacturing so you can produce the phones that are ordered. This will be very hard as you will have to buy the motherboard, camera, case, acceleromitor, gyroscope, cpu, battery, etc. from a manufacturer and that wont be cheep.
Finally you need something revolutionary. This coinsides with the third reason but you need to be able to offer something everyone else doesn't so you can compete. Wether this be the best bang for your buck, most powerful, slimmest, 3d screen, etc. doesnt matter. You just need something that can differentiate yourself from the others. So you stand out and make people want to buy from you and no one else.
I dont mean to kill your dream and by all means go for it, but I simply dont think you will be as big as Apple, Samsung, lg, etc. since they were able to start much earlier in the game and have vast amounts of money.