Step 4: Apply a grid
Now, with your barebone mockup in hand, you can define the grid. It's essential to carefully consider your grid at this point, as it'll help speed up your workflow further down the line. Depending on the content, you can settle with a more traditional, proportional column grid or choose a modular grid for a content-heavy website. You can also play around with asymmetry for more interesting, unexpected layouts.
Pro Tip: More columns mean more complexity. If you strive for simple solutions, stick to simpler grids.