Continuing in our "age series", your 20s are a thing of yesterday's past. By your 30s you should have built a decent collection of suits for work; and while its still okay to keep formal wear in the work place only, you should put great focus into developing just as respectable a range of casual-wear as that of your formal. Combining fashionable with flattering - its time to go through your closet and evaluate those items from your 20s such as hoodies, excessively tight, baggy or distressed jeans, and anything that can easily identify your taste in music. Your in your 30s now so find a good medium between professional and casual. Think about pairing good shoes with jeans, throw out those t-shirts and replace them with shirts, and introduce casual trousers and decent coats rather than bubble jackets and those from the brand North Face. While no age has a place for such misinformation, now it is extremely important that your clothes actually fit - thus your underwear needs to be concealed at all times.
And with you, your accessories should be growing up too; a decent precious-metal sports watch is a good place to start. Throw out rucksacks and bring in its place canvas or leather satchels. And I know what your thinking...no, you are not considered a decent human being if you still have a nylon wallet in your back pockets. Only leather will do.
In other words, time to smarten up your act without losing your youthfulness - with you no doubt should be treasuring right now.