which topic should i use

There are lots of options , the easiest once to start are :

1. To work on a topic you are good at .

Just come with a list of all your hobbies, interests, experiences, your educational background, etc and pick any one you are comfortable with .

Make also sure that the topic is profitable .

2. You can build niche sites

Pick a niche with money making potential and low competition in the search engine results page

Hope it helps.

Yep, you should always choose the niche you know the most and/or the niche you're passionate the most.

You seem to be a little lost. That's ok at the beginning, everyone starts somewhere.

My advice to you is:

1. Choose a market and stick with it - Choose something you have an interest in or are passionate about.

2. Pick a product in the market - Pick something that you know converts and is hot at the moment. Don't try to promote old stuff, you may have a hard time promoting any such products.

3. Decide on how you are going to drive traffic to your website - Again, if you are brand-new and on a budget, you will probably want to start out with free methods, such as SEO, video marketing, forum marketing, blog commenting, Craigslist and similar. If you have the experience and money, you can drive paid traffic to your website, too.

4. Test and track, observe conversion rates and adjust - Try different positioning of your ads/banners/text links (whichever you are using to promote the product). Be creative, not static. See what works best for you and stick to it. Squeeze the most out of your campaign and only then move onto something else.

You can start with the hobby you are interested in, or stick with some hot trending niches.