There is no “I think” when improving the site’s effectiveness.
There is only “Based on research insights X, and analytics data Y, we should test Z”.
Best practices and “I thinks” can only be applied if there are things that are blatantly wrong with the website.
For everything else bring data. Provide research. Give a reason why, different than “I think”.
If not, you might as well live by this quote by Jim Barksdale:
If we have data, let’s look at data. If all we have are opinions, let’s go with mine.
When you’ve been improving websites’ effectiveness for 9+ years, as I have, it’s easy to fall into a trap of starting to fix things as soon as you see a website. But even with such an experience it’s usually hit and miss.
Nothing can beat research and ideas that come out of research. And I don’t even start looking at a website if I haven’t looked at the analytics.
Sometimes, when you want to rush things and get straight into fixing, you do need a Batman in your life to set you back on track.
PS. If you want me to be your Batman, let me know. I’ll be gentle but firm.