Blazers..

[TheFashionPrinceHeir]

Coming from an 18 year old whose friends all wear the most laid back clothes ever and to whom a shirt is much too formal, whats the best way to wear a blazer casually? I have a navy and grey one, rarely wear shirts...on top of a t shirt? Crew neck, v neck, slouch? Plain, striped? How many buttons should the blazer have? All open for casual look? Sleeves rolled up? and what to pair with, jeans or is that the 40 year old dad look, bright chinos? Thanks

[CTurbinado]

i really do not like to see blazers with the sleeves rolled up...

[Olly]

i really do not like to see blazers with the sleeves rolled up...

You say that but watch Miami Vice. Too cool.

[Perry]

I guess it depends on the type of blazer you have, an unstructured one would be great for the summer. I'm also not a fan of anything other than a two-button, although one is much better than three (only button the top one on a two-button if you do button it up - keeping it unbuttoned is probably more casual though). A crew or v-neck t-shirt, striped or not would look great. Neutral colours is always a good rule of thumb. Navy blazer, white tee, beige chinos with a pair of white converse on and you can't do much wrong. I have to agree with CTurbinado though, I'm not too much of a fan of rolled up sleeves on a blazer. No matter how you wear it though, your friends will probably see you as being overdressed, so wear it for yourself.

[Sam]

If you're wearing it over a tee, you can push the sleeves up - as long as you don't mind crinkling the jacket.
A deconstructed, Allsaints style piece would be the perfect piece for that particular look, and a good starting point for the relaxed dresser looking to try out casual tailoring. And as a general rule of thumb, more buttons = more casual, so while a two button is the most classic choice three (or more) buttons could also be a good move here.
As for the tee, plain, striped, printed, crew, henley, vee, subtle scoop, all fine. Just avoid graphics and bright colours and you should be alright (bright colours can work, but done wrong you become One Direction)
Here's an example of a very casual look using a blazer - everything's from Allsaints:

I was going to use a sand coloured henley or something... but I couldn't resist including that tee when I saw it.

[Suminto]

With the navy blazer: it match well with just a plain white v-neck tees, and if you wanna try red chinos (not bright ones) with cream colour chuka boots.
With the grey blazer: you could go with either crew or v-neck washed out red tees, beige (neutral) chinos and cream coloured chuka boots.

Depends on the material of your blazer, if it is the summer blazer type do not roll it up instead just pull it up. Other than that, it better not to roll the blazer sleeve.