Polka dot is a classic pattern, like houndstooth, checkers, or plaid. You can look really cool with it or ending up looking like a walking Dalmatian. The key to select which polka dots to wear and where to use it on your outfits is the amount of dots and its size.
I would recommend to start with small items on your clothing, mostly with your accessories.
Tie,scarfs and handkerchief or even your socks. Pick one of them to start. Polka dots can go with many patterns as long as you remember to keep one pattern is larger and bolder. If you pick a bigger size polka dot pattern, then minimize other pattern on other items on your outfit and vice versa.
Also, it is best if you stick to just grey, black or white color dots. The background fabric must go with the entire out fit or to be safe, must be in the same color hue of your shirt or suits. If you choose to go with colorful dots in many colors, then the color of background fabric really must stay in the same tone as the shirt (like the one in the picture). Either the dot or the background fabric color must match the color way of your shirt or your suits.
When it comes to printed polka dot shirts, try to use small dotted pattern instead of a large one. If you decided to wear polka dot shirt, wears plain pants or trousers and keep everything simple. If you are brave enough wear polka dot pants, this is the one without exception, the pattern of the dot must be small and keep the rest of your outfit plain!
When use polka dot scarfs, its another story. You can go a shade or 2 lighter or darker from your shirt or suits color. which ever your preference is.
You can also choose different color scarf as long as it stays in the same spectrum of your base color. Remember if the base color of your polka dot scarf is brighter, your suits or shirt must be darker to balance the overall look of the outfit.