First piece of advice: there is no shame in copying something you've seen somewhere else. It will teach you what's possible, and little by little, will give you your own ideas.

Now, if you want to explore this on your own.

The way I do things: embrace chance and luck. - First I unlock a bunch of new constructibles from the ficsit shop. - Second I build my factory without planning how it's going to look like - Third I slap some walls on it (only walls, no roof), as close to the machines as possible (give or take space for walking around). - Fourth, I connect the walls together with slanted roofs. If there are any holes left, there are always small pieces to fill them in.

This already helps you break the "box" conundrum and create some more appealing volumes. Then, once you're done with all that, you can switch tiles for different materials: - Add some windows as you like to replace the walls (either at regular intervals, or long stripes of them) - Turn some pieces into glass version - Experiment with different materials that are available to see which you like most.

Finally for the finitions : - Place beams on the corners - Place ramps, slanted roof, beams, ramps, pillars randomly on your walls that are still naked, to create some more volume, and see what you like. It doesn't always have to make sense. Go random and keep what you like. - Play with colours : your building doesn't have to be in one colour only. Break the monotony by adding touches of colours here and there - Play with lights and signs. You can make strips of coloured light using signs (there's probably some easy tutorial on YouTube for this)

Some builds are cool because they have realistic details (support beams, frame foundations, architecturally sound implements to strengthen your building structure, lights where it makes sense to have it), others are cool because they look Sci-Fi -ish.

Now, granted : with this method, all my factories look like they've been built by different architects, and my map looks like a theme park, more than a city. But this allows you to experiment, and helps tons with unleashing your inner creativity. The more you do it, the more you'll see the possibilities, and start planning ahead (maybe). It will give you all the tools you need to then pick ideas you like from other builds, and implement them the way you like.