1. What kind of industry should I consider so that I can get easy traffic in a very, very short amount of time, considering the fact that my only objective is to reach $2000 monthly.

Health/wellness/nutrition/fitness are usually quick, high-interest industries. Definitely high-competition, though. Saturated market already.

2. What could be the most efficient way to get traffic in this case

Efficient? Buy it from Adwords. COST efficient? Organic/SEO. But organic takes time and lots of energy in content production and promotion.

3. Should I use Wordpress blog or design my website from scratch (any other suggestions?)

I prefer WordPress for nearly everything. Unless you have some specific reason not to, I recommend choosing WordPress.

4. Is there another easy way to get money for my website apart from Google adsense?

Yes, definitely. Adsense is actually a VERY low payout method of monetizing traffic.

Look into CPA marketing, or cost-per-acquisition. Affiliate marketing sites are also good options. Both take time and effort, however.

$2k/mo in web traffic revenue is a lot for solo publishers. That's an ambitious goal. Chase it, definitely. But think outside the box a bit. Adsense won't get you to $2k/mo anytime soon.

If there were (legitimate) get-rich-quick schemes lying around on the web, we'd all be doing them!