We, the authors, would like to state that after years of trawling through UX and UI guides have decided that the vast majority is absolute crap. What you read here obviously isnt crap, or at the very least - is crap of a vastly superior, more cynical vintage. We are sure you will agree. And indeed you will, if you know whats good for you.
All the stuff you want to do, don't do it. Just.. stop. All that stuff you feel you have to do? Yeah, you don't. Nobody wants you to do that. Least of all your users.
When your finished stopping, open up a random page on your app and proceed.
What the hell is going on here? What do you want your user to do?
Remove any item that takes attention away from the user performing the thing you want them to do right now. That includes pictures, graphics, headers, menus, navigation, options, buttons, links, footers, advertisements. Then, structure the remaining items so that its clear what they should do and in what order, to proceed.
Where is the user going - where have they come from?
If this page is part of a process for the user, make sure they are able to go back, go forward and cancel. It must be amazingly obvious, as your users have the collective IQ of a bunch of dumb people.
For every page. For every flow, for every app.
You can have a thousand features in your app but you gotta structure them well. You can bundle settings together so they don't pollute. Thats what a dashboard is for. But notice despite dashboard advances automotive manufacturers have had the grace to leave the steering wheel relatively unscathed.