Having a good sense of fashion is sometimes just natural to some people who maybe are arty or just simply because they have a certain touch in being able to put together outfits that look up to date, trendy and chic, but others have to learn it the hard way and as they say practice makes perfects and so you should get the hang of it in the end.
Sometimes you may have a relative or friend who knows how to do it and you are able to learn from them or another way is to buy fashion magazines and see how they have dressed the models for the photo shoots. You will realise yourself what looks very good and maybe if you see one outfit you can try and copy it, not necessarily by buying exactly the same clothes, but looking for items that are similar. As long as you have the idea and the colours in your mind you can hunt around in the shops for something that almost looks like the original model that you saw in the magazine.
Watching certain films where the actress puts on different outfits is also a good way of seeing whether you like what she is wearing and giving you and idea of what you want to look for when you next go out shopping.
And of course the last way is to watch those programmes on television where they concentrate on the collection of a certain designer where is where you will see the most amounts of different outfits all in one go. Most designer collections are comprised of day wear, informal wear, evening way and sometimes even bridal wear, depending on the designer.
Learn from what you see and each time you learn something you will get better at rigging up your own trendy outfits.