Great question (ignore the *****!)
There is a formula to success in any kind of modelling...
Get a portfolio of yourself in the right styled clothes for the market you are wishing to enter... you need to show variations of styles that a stylist would considee suit A. your shape and B. the current market. You also need to demonstrate in the photos a range of different moods in your facial expressions
Get an agent, find one that does specialise in plus size models, there are many agents out there that you can talk to to get the ball rolling...
Lastly, and this is the killer...it is all down to luck! If your face fits, and you are the right person at the right place at the right time, you can explode into the modelling world..
There are ways on creating this luck though:
No. 1.travelling anywhere for the next job, showing willingness above all else, as everyone in that industry is just so fickle and back-stabbing that one mistake and your career can be over before its started. This also extends to modelling parties, the social scene of the clients, you have really got to put yourself out there and it will cost you money to start with!!
No. 2. Doing the ground work on the first elements, getting the right portfolio from a respected Photographer (which is more expensive) can give you the initial exposure, the right agent with the right contacts will be very important also...
I could go on and on about this to be honest as I have been in and around this industry for 7 years and have picked up all the tricks...
Best of luck