If you're looking to upload an image to a blog post, for example, examine the file for its file size first. If it's anywhere in megabyte (MB) territory, even just 1 MB, it's a good idea to use an image compression tool to reduce the file size before uploading it to your blog. Sites like TinyPNG make it easy to compress images in bulk, while Google's very own Squoosh has been known to shrink image file sizes to microscopic levels.
Lastly, it's important to remember that paralysis by over-thinking is a real issue some struggle with. There's no pill for it (yet). Predicting perfection is a fool's errand. Get as close as you can within a reasonable timeframe, and prepare for future iteration. If you're traveling through your plan and determine a soft spot at any time, simply pivot. It's many hours of upfront work to get your strategy built, but it's not too hard to tweak as you go.