Looking casual while you're wearing a tie is difficult but possible.If you need proof, just look at Jarvis Cocker.
Despite DJ'ing up a storm (we didn't hear it but let's assume) he still managed to look smarter than half those in attendance.
The stand out item in his ensemble is his tie - without it he'd look like the kind of guy who's just a little too old to be attending nightclubs.
With it, he looks like the kind of guy who has somewhere else to go but decided to drop in and see what was going on. The great thing about this outfit is that you're likely to have all the items already bar one, a casual enough tie for the weekend.
The ideal solution to this is a knitted tie. More casual than a worsted wool tie, it's the ideal halfway house for those times when you don't have to dress up. If you're planning on making it the standout piece of your outfit, it's worth spending a little bit more on it.
Drakes know a thing or two about ties (Drakes, £95) and this knitted tie shows off what they do best. Wear it with a soft shouldered blazer, white shirt and suitably worn in jeans to perfect your Jarvis inspired look.