Talk, especially to someone who is outside the main topic;
Read something at random to spark the synapses;
Summarise the challenge, again, in just 100 words;
Imagine you had no budget, twice the budget, the competitor's budget;
Give a deadline: 5 great ideas in 25 minutes.
But above all; break the pattern of staring at your screen, vaguely 'batting' e-mail and hoping for inspiration.Or sitting in yet another PowerPoint heavy meeting with little to consider except curling BLT sandwiches. Screens and e-mail are dulling not enlivening. Poorly run meetings are trance-inducing. Break the pattern.
1. Clear mind-1. Write down and 'forget' the stuff you don't want to consider at the moment. Put it aside for later.
2. Clear mind-2. Walk to gain perspective and oxygen. Sip water.
3. Clear desk. Have at least your main working area free of too many physical distractions.
4. Clear process. Request/insist on some interrupt-free time. From people, from mail, from phone.
5. Clear issue. On what do you want to focus? Define it.
6. Clear action. Get to work.