This tip comes from NPR, but its good for commercial radio & TV as well.
The NPR Training Site has six tips for catching your writing mistakes & and protecting your credibility.
The article linked above goes in-depth on these six tips with links to a variety of helpful sites including news checklists. Spend a few extra minutes with it, if you can.
Quickly, the six tips are:
1. Reread it
2. Change The Format
3. Step Away
4. Spellcheck and grammar check are your friends
5. Use a checklist
6. Recheck the most important stuff