​Advice for a new business idea?

Hi all, I have an idea for a product and a target audience in mind, but I would like to make sure I do everything I can correctly. In the past I started a clothing brand and while I found minimal success, it was just that, minimal. I had very little clue what I was doing and felt like I skipped many steps, lost money where I didn’t need to, and never fully honed in my product, brand, or focus enough to become established in the way I was seeking. The business landscape has changed significantly with AI in the past few years and I was wondering what tools I should be using and things I should be looking out for to set myself up for the most success? While it seems like this is rarely the case, are things like brand coaches, strategist, SEO specialist, or any of the like worth it, or are these skills more important for a founder to have? Where can I go to fully understand everything I need to and should? One of my biggest concerns personally is that while I have a great product In mind and somewhat of an audience, I don’t think it’s clear/niche enough to really capture in ads. Where can I go or what kind of people/tools can I use to help me improve this and overall make sure that I’m on the right track and not missing anything vital for the successful of this business? I know this post may be very telling in regards to how little I know at the moment but I would love to learn and really fully understand what I need to do to. Thank you all in advance for your help!