Fresh herbs are absolutely delicious, far tastier than dried. Some are even nearly impossible to over use when fresh, like basil. Basil, dried, can easily ruin a dish if too much is added. On the contrary, you could add an entire basil plant worth of fresh basil leaves to a dish and it won't be ruined (yes, I've tested this theory).
Freshly chopped dill
Sadly, fresh herbs aren't always an option, so dried herbs get used a lot, too. They cannot be used in the same proportion (as mentioned above with my basil example), so how much DO you use? Easy! Just add dry herbs in 1/3 of the amount called for in fresh.
1T of fresh = 1t of dried
Of course, opt for fresh if possible. When it's not an option, don't forget it's not a 1:1!
Disclaimer: Thoughts of Fluff was not compensated for this post.