Start with a Retrospective. Gather data about the teams experience. Find the pain points. People are most motivated to find ways to reduce their pain. Brainstorm solutions, find champions for those the agreed solutions. I often have a designated buddy to support the champion.
You might have to talk to management separately about what they are trying to achieve by interfering. Usually it is about control. Find out what it will take to reassure them. Maybe its a demo at the end of the sprint or at a regular cadence if your doing Kanban. Maybe its some sort of regular report. I found there are all sorts of fun metrics you can exact from your task tracking, version control, static analysis, support ticketing, build systems etc. I am a big fan of automated reports and dashboards not such a fan of hand made ones. You could use information radiators. Or maybe they just need a regular chat.
Ultimately its about trust. You should encourage them to talk and drill in deep, not accepting anything at face value. Don't be in a hurry to rush in and explain things. Let them have their say and make sure they feel listened to.
If you need to change a practice go back to the principle behind the practice and ask is there another practice that follows the same principle.
If you need to adjust a principle go back to the value behind the principle and ask is there another principle that will help promote the same value.
However do not lose sight of what you are trying to achieve.