They don't all look the same. They all tend to go to different places. I find that it's reasonably easy to spot a great deal of garbage sites just from their domain name or url, and that weeds out a large chunk. Ignoring multiple results for the same site also weeds out a large chunk (I only need one of them).

The rest, I just click on and take a look at the page. It's pretty quick and easy to weed out most of the garbage ones with a quick skim.

The rest, I sample, read captions and boxes, skim paragraphs and such to determine if it's along the lines of what I want. That's pretty quick too.

For the most part, it's the same process that you use when researching in a library.

The reason that I want to do this myself rather than outsourcing it is because I'll inevitably learn something in the process that will shift my viewpoint to one that's more targeted or meaningful for the purpose I have in searching.

It doesn't matter how good the engine is at collating and summarizing results -- even if it's perfect, my understanding not only of what I'm looking to learn, but also discovery of important but serendipitous or unexpected knowledge, is lessened.

It's a bit like the difference between reading Cliff's (or Cole's) Notes about a book and reading the book.