I suggest simply learning to avoid godmodding the first time, which Hikaru will teach you about when you take the Don'ts class. As for lengthening your posts, you need to learn to use a decent vocabulary and writing skills to increase the amount of detail in your posts. For example, instead of:
Vailen mumbled a few words, and wings appeared on his back. He then flew over the canyon he was standing next to.
You could use something like...
Vailen, seeing the rather large chasm before him, knelt down and clasped his hands just below his chin, closing his eyes in reverence. "Divus, dare me connatus Alae placeo!" He chants, low and strong as his face lifts up towards the heavens. His face turns quickly into a grimace of pain as the sound of ripping fabric echoes across the empty, rocky plains. He arches his back hard, causing his spine to crack as he screams out in pain, great white-feathered wings bursting from the flesh on his shoulder blades, spraying blood out behind him. Kneeling forwards and panting hard, Vailen slowly rises to his feet, giving his newly acquired, albeit temporary, wings a few beats to test them. With a pained smile, he gives himself several yards of space before the ledge, and takes a slow, deep breath. Charging forth with all the speed his legs can grant him, he tenses his wings and leaps over the edge of the canyon wall, gliding through the air for several moments before angling downwards, accelerating at a magnificent rate before quickly leveling out, and then pitching upwards, just barely making it over the edge of the cliff wall opposite of his starting point.
Now, I am going to give you a situation, and you are going to write two posts. First, using your normal rp'ing style, then useing an expanded vocabulary and detail to lengthen it.
I will give you a day to prepare if you like. Have someone let me know via IM as soon as you are ready. I will then post your situation, and you will have one half hour to post your normal post, and an hour and a half to post your lengthened post from the time I post the situation. You do not have to use up all the time, and I will be using the post times to verify that you posted within the time limit.