First things first know what basics you have in your wardrobe.
These basic tees and blue jean and what are going to bulk out all your outfits after all you wouldn't want to wear a head to toe statement look. I tend not to spend too much on these items but make sure they fit great.
Now on to the other side of your wardrobe with what I like to call the attention seekers.
These items are most likely printed or have a really unusual texture to them and can be anything from a blazer to shorts or trousers or even a scarf. I get these kind of things from flea markets and vintage stores they loose there quirk if everyone else is wearing that same printed Topshop blazer. Things like this are great because when your wearing one item that gets all the attention no one will even notice that your wearing that same white t shirt you wear three times a week and even if they did they would only be thinking how chic you make such loud clothes by mixing them with your effortless basics.
Next... start collecting jewelry rite now...GO!
I don't really like to spent a lot on jewelry unless they are real investment piece i have four very expensive pieces. I have a vintage Dior necklace from my grandmother, a pear necklace and a ring off my mum and a delicate gold necklace with a sapphire and diamond pendant that was from my boyfriend and I think that that is enough. sure there are a few other piece that would be nice to splurge out on but they really just aren't necessary. i tend to just buy a lot of costume jewelry from Topshop and markets Dorothy Perkins if your in the UK has some great sale jewelry and also forever 21 is great too. If you buy a piece of sale jewelry for £5 every two weeks by the end of the year that's 24 new pieces of jewelry for just £2.50 a week easy to do on the lowest of budgets. then just pile it all on and really be brave mixing and matching.
Find some really great outer-wear and splurge as much as you can on this.
I truly believe that your coat will make or break your outfit. Go for coats with unusual details like nice buttons, hoods, buckles and embellishments and that fit you amazingly if you don't they just look sloppy and do the opposite of pull your outfit together.
Lastly get that effortlessly cool rock and roll hair and makeup nailed to go with that I don't give a damn attitude.