Amazon fantastic options. Amazon is personally my favourite one. Read up on its basics on how one can sign up for an Amazon Associates account (plenty of info on web), find a product to promote.. Write a hub HIGHLY relevant to that topic (you need GOOD quality stuff to succeed here!) and link to it in your hubs. You'll get more than 4% of the total price of the product on Amazon as an affiliate.
Adsense is definitely a good option but I personally haven't had a lot of success with it, plus you'll only get a little fraction of earnings. No harm to put it on anyway, but keeping Amazon as your primary source could earn you a lot if you do it right.
Just remember to keep your focus on providing content that people genuinely find HELPFUL. That's it. Slap pointless and irrelevant affiliate links at people and they'll slap the "back" button leaving your earnings at $0.
All the best.
P.S. There are TONS (literally TONS) of pages on web that mention how to earn from Hubpages the right way. Many of them you can find on hubpages.com itself. Look around my friend, but remember the details I mentioned.