Style on a Sunday: Festival Fashion

There is now only 5 weeks until me and Ryan head to Knebworth for Sonisphere and due to extreme lack of funds I am unable to really buy any new clothes for the occasion. So, I'm starting to plan now so that I have a vague idea of what I need to pack nearer the time. In my experience it is most important to have simple outfits which can be mixed and matched with accessories/shoes/layers depending on weather. So, here is my first Sonisphere outfit:

Dress: Zara, Shorts: New Look, Belt: ASOS, Socks: Primark, Boots: Hunter, Bag: ASOS, Sunglasses: Claire's Accessories

Here I have my simple outfit of a dress and shorts which I think would be great for a typically muddy but warm festival day. However, if it was a boiling hot day, I'd take away the socks and wellies and add a pair of simple plimsolls (however tempting flip flops may be, I think I'd be in a world of pain if I stood anywhere near the front - poor toesies) like these from H&M:

Or, if it was a really cold day I'd add a plain black hoodie and leggings, and if it was rainy I'd add a thin waterproof jacket. The only thing I'd like to add to this outfit for a hot day is a hat, but I really don't think I suit hats so I never know what style to get!

What are your top tips for festival fashion? Please share your wisdom in the comments!