If a news story that is likely to dominate coverage in your target publication has broken that day or week, it may be worth postponing your PR plans. For example, if there has just been an announcement about the closure of your local hospital, you may want to postpone a press release for the local paper, as there will be less space for soft news stories.
If you have flexibility around when you send out your charity's press release, consider saving it for a quiet news day, or a quiet time of year. Mondays, in particular Bank Holiday Mondays, are often quiet news days for daily newspapers, TV and radio. Christmas and the summer holidays are quiet times of the year for most publications as there are less government stories.
A story with a weak news hook can often be improved by linking it to an event that you know will attract coverage, such as Easter, GCSE/ A-level exam results, Bonfire night, Remembrance Sunday or Christmas.
For example, a charity's story on mental health problems among young people could work well on exam result day; a story on hearing problems could work well on bonfire night. Or, if you want PR for your elderly charity, why not interview a client who fought in the war and give the story to the local press in time for Remembrance Sunday?