In General
There are very few hard & fast rules about what to wear for your headshot. So – keep it simple and don’t get stressed or overthink it. For this type of portrait, the emphasis will be on your face – not on your outfit.
The most basic guideline is to wear the clothes you are comfortable in – depending on the photo purpose. This is often your standard business attire, whatever that may be. Think along the lines of what you would wear for a client or external meeting.
You should also consider where your photo will be used (e.g. on a Team Webpage), and how it will fit in with any previous images there.
So, in some situations, you will be free to wear anything you want. In others, you might have to adapt a bit.
Specific Tips
Aim for classic, timeless clothing and accessories, of whatever style
For more formal clothes – make sure the fit is good, with no obvious wrinkles. Photos can emphasise any minor issues
Feel free to have some extra clothes along – you don’t have to try them, but sometimes they may work out better
Most colours will work – but very bright colours can be distracting
If makeup is worn, normal daytime makeup is best – nothing major extra. A quick check and touch-up before the photoshoot is all that’s required
If you normally wear glasses – then it’s better to wear them for the photoshoot. I watch out for awkward reflections, and have a few ways to work around them. Avoid tinted or photochromic glasses though.
For men, the photo can exaggerate shaving or lack of – so remember this to suit your preferred image
Avoid large/bold/busy patterns, broad stripes or logos & branding
If wearing a tie – avoid bright red