An interior designer says the biggest mistake you can make when painting your home is mixing colors

• Richard O'Gorman has spent the past year transforming his drab home into a colorful, cheery space.
• He started posting his designs to Instagram as "House Homo" last spring and now has 34,000 followers.
• O'Gorman told Insider that, after a DIY fail, he has one rule for painting: no mixing.

Richard O'Gorman has spent the majority of the past year transforming his home in Birmingham, England, from one that was "crying out for color" to one that is bursting with it.

From the hallway to the bathroom and kitchen, O'Gorman has breathed life into every nook and cranny of the house through bold and vibrant wall murals. Posting his designs and room transformations to Instagram, he has amassed more than 34,000 followers to date.

This past December, O'Gorman learned the hard way his now-golden rule of painting: don't mix paints.

O'Gorman learned a valuable interior design lesson when his kitchen needed repainting

Over the summer, O'Gorman painted his kitchen using two custom shades: a green lightened with white and a pink made dusty with a "dash of lilac."

While the kitchen looked great, the pink paint started to need touch-ups as time went on, he told Insider.

"Spaghetti happened," he said. "I'm a very creative cook."

That's when O'Gorman realized he couldn't replicate the kitchen's original shade of pink for the touch-ups.

"I tried to mix it to match, but couldn't get it just right, so ultimately I had to start all over!" he told Insider.

It took O'Gorman a couple of days to redo the kitchen's pink layer, and in a rush to repaint on New Year's Eve, he set off a chain of unfortunate events.

"I fell off the cabinets painting recklessly, crashing to the floor and spilling some of my freshly mixed paint and bruising my body and pride in the process," he said. "I then knocked over some art on the shelves, which knocked off a plant and smashed the pot. In a fit of frustration, I stormed out of the house and locked myself out."

"It was a terrible way to end what had otherwise been an amazing year!" he told Insider.

To avoid frustrations like the one he experienced on New Year's Eve, O'Gorman now sticks with paints straight out of the bucket.

To see more of O'Gorman's room transformations, follow him on Instagram @househomo.