If you like a particular designer and you choose fabrics that they create for various manufacturers...you can be somewhat assured that the color pallet that they use can be safely combined with most all the designs they create as to color. That does not take into consideration scale or pattern, but they too are human and tend to work within their color comfort zone. There are obvious exceptions and some designers are far more inventive but I still see a color commonality even when it appears they have veered off their more predictable design path. This seems to work for me: when you lay out your colors/patterns, if you squint your eyes so as to blur your vision and look at your choices...if one "pops" out as distracting...unless you are committed to its use...consider its removal and proceed. I see some people suggest using a door "peephole" for a similar purpose. Color is something that can drive people to distraction, but the first thing to remember is this craft is for your enjoyment and if you like it...use it, obviously within reason. However, if you are still uncertain there are free color classes on Craftsy from time to time, likely tutorials on the internet and then advice from others. It has also been pointed out to me, more than once, that men often think outside the box and that my color choices were daring, but not poorly chosen. Take what you pick to a person whose color sense and design combinations you admire, do it a couple of times and if they find what you do to be close to "spot on" then stop doubting yourself, build your stash like almost everyone and enjoy!
Hint: I also learned that the temptaton to buy a lot of fat quarters should be rethought and buying a third of a yard is the more economical way to buy most cut yardage...obviously "sales" excluded.