How do you decide what to put on your website?
The worst thing you can do is just add everything onto a few pages in a carte blanche style.
You want to think strategically. I'm not talking about any complex algorithm. By using a little common sense and a little strategy you can quite easily make the best decision on what elements you can add onto your website.
The battle for the search market
We all know how this battle turned out. Google has over 90% share in the market throughout most countries in the world. Yahoo has an almost zero share. If Google had gone down the route of adding everything, it's very doubtful if it would even have survived to the present day. Their focus and attention was search, Yahoo tried to do everything.
Client pushing for everything to go on the web page?
Whip out your mobile… there is limited real estate forcing them to choose!
The constraints of mobile phones force you to make design decisions. With the limited size of mobiles, you have to make priority decisions. Not everything can fit, so you have to prioritise.
Image #3 shows how the constraints of mobile force you to remove elements.
The magic of mobile-first is that when you have removed elements from your mobile design it changes things when you go to design your desktop experience. You now ask the question "Do we really need these elements on desktop \ laptop? [As we didn't need them on mobiles]" This question in situations and scenarios is answered no. This removes the cruft and non-essentials. This gives you clearer, better and more effective websites. Win!