There are loads of great spots in Bristol to explore, the city is full of unique locations, with many parks and nature reserves there’s lots to choose from. I personally like parks located near Clifton suspension bridge, here you can get the bridge in the background to some of your photos which adds something different to the shot.
A favorite of mine is to use local nature reserves, you might have to do some exploring but with a bit of effort I am sure you will find something special.

