It's important to understand how much behavior around technology is based on ingrained habits. My goal with dealing with my phone was to "short-circuit" the habitual/addictive behavior.
To do this, I did two things.
1. I turned off all automatic notifications on my phone, as well as all background updates of apps/email/etc.
2. I created a simple rule: I can use my phone whenever I want, but I have to wait five minutes after 'thinking of using it.'
Combined, these two rules have been effective in short-circuiting the addictive properties of my cell phone. The five minute wait time gives me the chance to have deliberate/conscious thought about my phone use. The lack of automatic updates happening in the background gives me a chance to catch myself, if I unconsciously start using my phone. For example, it takes 20-30 seconds to load email. If I unconsciously open the email app, nothing has changed. Sure, I can tell it to load the email, but the time it takes to load the email gives me the chance to realize I'm breaking my five minute rule.
I feel like I'm able to use my phone as a tool again. After around a month of this, I'm no longer scared of my phone's power over me.
Sadly, I haven't figured out an effective system for my computer yet.