So, whilst we’ve spent a good amount of electrons discussing proper accoutrements which ride patrons would be well-advised to consider, most of what has previously been blathered over are personal accessories. One would properly ask, “What about the bike?”
Now, we certainly don’t expect everyone to rush out and purchase a brand-new set of cream-colored tyres…

Schwalbe Fat Franks, if I'm not mistaken
…there are numerous other ways in which one may accessorize one’s ride. One of the most obvious areas for dressing up one’s particular vehicle is the top tube:

A snappy argyle
Yes, the top-tube-pad comes to us from the BMX world, where it had formerly been required equipment, considered as necessary to ensure survival of the species. More recently the top tube cover has been hijacked by the hipster/fixie (“fixter?”) crowd.
The top tube pad/cover is now available in a variety of styles/colors/patterns/textures.

Note the faux-houndstooth pattern near the centre
The more enterprising types can even make their own top tube cover:

A bit hirsute, perhaps?
Perhaps a more traditional area of adornment would be the custom head-badge:

headbadge-in-the-making
There are a number of folks who now offer custom-made head-badges in any number of styles. True artists making, in effect, pieces of bike jewelry.
Some of these can be quite pricey…

One craftsperson is making a piece particularly befitting our theme. The “bike mustache” would immediately identify the rider as a tweed ride patron…

The 'stache for your steed
Time to spruce up. We’ll see you in a week.