If you're having trouble flying there's a few things you can do... I used to have trouble, still do when I have a dumb moment but much less than before doing the below.
1. Do not go through the expense of a trainer, when you can use something like this as it will suffice.
https://play.google.com/store/apps/details?id=com.Creativeworld.QuadcopterFX
I am sure you can get something similar for iPhone, but after a few hours of playing with this controlling my quad outside and flying everywhere was sooo much easier to get my head around.
2. And this will help no end, simple stuff that will enable you in a short time to get used to flying. The arrow thing is a bit extreme, but 'Walking The Dog' is valuable.