It's more simple than you think. Here's a quick and easy example from my own family room's coffee table. I'll even link a few favorite items to help you get started.

Photo credit Laura Fritz Photography.
Start with a large tray that will fit several decor items. The size will depend on your coffee table - but when in doubt go big. This is a place to add texture too! The one I have is rattan and I love the way it looks against the books and greenery. From here, the world is your oyster! I selected a few of my favorite coffee table books, two greenery items and a medium size glass hurricane and filled with a candle. It's February so any chance I get to add live plants to the house, I do. This room gets a lot of natural light so plants and flowers do pretty well here.
The flower pot is terracotta filled with tulips, hyacinth and paperwhites. I love the contrast of the natural terracotta finish with the defined rattan scallop tray and vinyl coffee table. And you won't believe where it's from (or maybe you will). Trader Joes! It's now bloomed completely and the hyacinth and paperwhites are truly a beautiful addition to the tulips. If you don't have a Trader Joe's nearby, you could easily recreate this with bulbs and preserved moss.
The bubble texture on the glass hurricane create a more casual feel to what could otherwise be a formal decorative piece. I was drawn to it immediately when I saw it at a local store.
The easiest addition to any coffee table is of course, coffee table books! You can never have too many - I'm always adding to my collection. Add an object or two to the stack of coffee table books, and voila! you have yourself a styled coffee table.
The picture below shows how the plants and objects hit at different heights and the various material of the containers, plants and objects create interest.

Photo credit Laura Fritz Photography.
Coffee table is 100% kid-friendly. Like we're talking spilled well, everything. And it's all wiped up without a stain and no amount of imaginative play with robots, legos or blocks has made a mark on it. The material is vinyl upholstery, and it was custom made through Ashley Walters Interiors. Sorry I don't have more information to share!