A home improvement project is the culmination of a thousand tiny decisions, but the single choice that creates disproportionate anxiety — the one that wakes you at 3am, muttering: “Amish Fig or Chafed Hare?” — is colour. However breezily they tell us in B&Q that changing an unfortunate paint colour is the work of an afternoon, we know that if we choose, for instance, Heart Wood (the chocolatey heather hue that Dulux has declared to be the colour of 2018), and end up hating it, we’ll probably live with it for years anyway.

Nobody understands the importance of our colour choices better than Tricia Guild. In the foreword of her latest book, Paint Box (Quadrille £25), she writes: “Many people… are more than a little nervous of embracing colour. There is a reticence and anxiety that prevents them from choosing anything that might be a little daring.” Guild aims to help us make courageous decisions — but, ironically, choosing between the 45 delightful colour palettes is enough to keep anyone up at night.

All white on the night
Many domestic decorators pick white, believing it to be the default setting, a non-colour that cannot offend. Well, yes and no. It needs cautious handling in the home: bright white plus startling colour can equal a jarring or “wacky” interior. Which is fine if the look you are after is “Google HQ”.

There’s a world of difference between brilliant whites and soft whites. Dulux is rightly renowned for its whites, and its brightest is the dazzling Ultra White Matt, made with LumiTec “optical brightening technology”. For a more tranquil scheme, choose a gentler shade such as Eico’s Painter’s White.

Pretty in pink
Your wardrobe provides a good starting point for choosing a colour you will love to live with. The hues that suit you, and make you happy when you look in the mirror, will probably please you on the wall. Flattering colours, often overlooked when we come to decorate, include pinks and lavenders. The hints of warmth in these shades play well with northern-hemisphere daylight and complement most complexions. Top picks are Farrow & Ball’s Pink Ground, which has been joined on the firm’s colour card by a bluer cousin, Peignoir. Pippin in Spring, from Paint by Conran, is a delicate blush, and Osterley is a sweet “shell-like pink” from Mylands.

Shady encounters
For a more dramatic look, consider going dark. Glamorous “bottom of the lake colours”, popularised by Abigail Ahern, who launched her own paint label in 2013, have become the mark of the covetable interior. If you are scared of the darks, here are four reasons to give them a go:

• A dark backdrop is the perfect accompaniment to metallics and mirrors.
• Darks turn small rooms with little natural light into cosy, cocoon-like spaces.
• They are the opposite of an unforgiving brilliant white, rendering bright colours jewel-like rather than jarring.
• Sticky fingerprints show up less on dark paintwork.

Apart from Ahern’s own label, consider Benjamin Moore (Gentleman’s Gray), Little Greene (Hicks’ Blue), Paint & Paper Library (Plimsoll) and Farrow & Ball (Hague Blue). The F&B shade is the decorators’ favourite — though some of the firm’s paler paints have needed an injection of up to 20% more pigment, after complaints about coverage and opacity.

Testing, testing
Once you have an idea of your palette, look at the architectural features in your interiors… then banish them from your mind for ever.

Don’t pick out skirting, cornices and radiators in a contrast colour. This is fussy and dated, and makes a room appear smaller by creating a (usually) white cage around it. A block colour from floor to ceiling is calming and contemporary, and works well with a matching or contrasting ceiling.

The most common colour for a ceiling is a shade of white, for the practical reason that it bounces light around the room, but a dark ceiling in a dark room can be spectacular, making the space above feel limitless.

Paint firms invented the test pot to aid the decision-making process, but buy too many and you risk analysis paralysis. The best advice I’ve heard on the subject, imparted by Joa Studholme, of Farrow & Ball, is to paint the samples onto large sheets of paper and Blu Tack them to walls, rather than painting the actual surfaces. Try the sheets on different walls at different times of day, bearing in mind that colour appears different in every light.

App happy
There are plenty of hi-tech toys that can help. Valspar’s Pick-a-Paint app lets you virtually test how a colour will look on the wall. Similarly, with Dulux‘s Visualizer you can select a colour and see how it will appear in an augmented-reality version of your room. If you’re still having difficulty narrowing down your colour choice, save the result as a video or photo, which you can share with family and friends via social media. Fingers crossed they won’t lose any sleep over the problem.