Watch the Solo Structure online guitar lesson by Angus Clark from Focus On: British Metal
For the most part British Metal tunes are structured like pop tunes, so keep this in mind. You need to be economical in your choices. Having an idea of what the solo needs to accomplish in terms of energy level and emotion is key to getting the right vibe out of it. Also generating a "song within a song", a solo that has a beginning, middle, and end, is key to success. Take a step back from trying to come out of the gate blazing. Take a breath. Then go get 'em.