One of the things that might help you is this: Understand why the resistance is. It may be true that things are working today but if your suggestion means that

One of the things that might help you is this: Understand why the resistance is. It may be true that things are working today but if your suggestion means that you only make it better/faster/whatever in support of whatever your team’s strategic objectives are , it might win you your team-mates’ confidence. As a new member in your team, there might be people who view your ideas with skepticism and it’s natural until you can show that you’re only suggesting things that will make life easier for them