Usually for the plain block coloured dresses I stick with Primark but for fancier or more trendy options I'll look online before purchasing one.
Here are three websites which feature some fabulous choices, along with my top picks:
MissRebel.co.uk - For a night out or a party this classic black dress takes on a sexy side with sheer panels
HouseofFraser.co.uk - I love this Grecian style dress, it's perfect for daytime and would work really well with a cardigan or jean jacket for chillier evenings in the summer
Myeveningdress.co.uk - This is perfect for all you girls who need Prom dresses. They come in a variety of colours and are on a special offer at the moment. This would go really well paired with a twisted updo or braided style.
Those are my picks. Let me know in the comments what your favourites are for this season and summer!