The first thing you need to think about is which people you should contact, because you want to make sure you're contacting people who might be interested in your content. If you contact people randomly, your response rate will be much lower, and you'll probably give yourself and your website a bad reputation.

Ideally, before you really start a link building campaign, you should have a rough idea of who you think will be interested in what you're doing. If you're creating content that you want to link to, such as an infographic, at the very beginning of the process you should ask yourself who will be interested in it. More importantly, who will care about actually linking to it?

This last bit is crucial. While it may be fairly easy for you to get people to look at your content, it's a whole new level of engagement for them when they actually link to it. Linking to something takes a little bit of effort and time, so you need to make sure someone cares enough about them to not mind it. The barrier to sharing your content on social media is much lower. More people have a Twitter or Facebook account than a website or blog, which makes it easier for them to share information. 
So how do you make sure people are interested enough to put links up?

You need to find a hook that gets people interested. You need to incorporate that hook into your content from the beginning. If you put off thinking about your hook until after you start your work, you may find that no one cares about the substance of your content, resulting in you wasting a lot of time creating content that no one wants to link to. k. Some hooks you might think about are: News, Funny, Controversial, Data visualization,Competition,Ego-baiting,Long, detailed content . 

There are many kinds of hooks, but the ones listed above should at least make you think about what you can offer people that will make them link to you.

There are some simple ways to figure out what works and what doesn't in your industry. Starting with the basics, just start looking for topics that are relevant to your industry and let yourself get a little lost. Check off what's interesting to you and add interesting content to your bookmarks.