I need a strong Suggestion

Hi all dear !
I am a graphic designer. and i working on many wordpress websites of my clients. but last year i create my portfolio in wordpress. and after 3 months my wordpress portfolio is hacked. then i never install wordpress in my hosting.
But now i want to start business on a wordpress website through google adsense.
I need all your experts strong suggestions. Can you people tell me about:

1: what type of wordpress theme is perfect for SEO and adsense too.
2: how can i secured my wordpress website from hackers?
3: what type of plugins you recommend me for Security , Video player , SEO , and Adsense.
4: If i want to create wordpress theme my own self, what type of tutorials i follow?
5: How can i generate traffic on my wordpress website?

I am waiting for all your expert opinions. Thank You