It sounds obvious, but it bears repeating. Where once more slender chaps were plagued by sloping shouldered jackets and shapeless trousers, there now exists a veritable cornucopia of slim and skinny-fit tailoring on the high street (and virtual high street). You might be not be able to achieve the 'made to measure' perfection of a bespoke suit, but a sharply-fitted two-piece that enhances your physique rather than hides it should be well within reach.
...But don't go too skinny
Your jeans might not leave much to the imagination, but your suit trousers probably should. Super-tight denim usually contains elastane to allow for ease of movement and to cushion your delicate bits – suit material isn't nearly as forgiving or flattering when stretched tight. Basically, if skinny rocker dude is your body type, look to the classically slim-line cuts of Alex Turner (above) rather than, say, the comedy crotch-crushing numbers favoured by The Horrors.
Tie one on
As a slim guy in a slim suit, it follows that you might reach for a slim tie. A word of warning though – going ultra-skinny can leave the whole 'fit looking a little cartoonish. A better bet is to roughly correspond your tie width with the width of your jacket lapel.
Check yourself out
One advantage to a lighter build is that you (like YouTube star Jim Chapman, below) can rock bold patterns and fabrics in your tailoring that might be a bit full-on on a stockier fella. Try a Prince of Wales or windowpane check for a fresher, more adventurous take on your basic smartwear, or go all out in a party-ready print.