I have two domains available to me, so it only makes sense to use one for trading. First of all, I'd like to gain some insight from people here about what they specifically want from a trading/banking site, and what precautions I should take against attacks. I'd like to have some sort of two stage security, whether it's worth it is another question entirely.

So:
What services should a new trader offer?
What banking services should be available in conjunction?
Is the likes of cloudflare a good idea?
What is an acceptable charging threshold? (I'm out to make a profit, as dirty as it sounds.)