Mnemonic Device:

• 1) Empty Garbage Before Dad Flips.
• 2) Good Birds Do Fly Away.
• 3) BEAD (B-E-A-D) Goes Crazy Forever.

Explanation:

• 1) Treble clef lines, bottom to top (EGBDF)
• 2) Bass clef lines, bottom to top (GBDFA)
• 3) Order of flats in key signatures (BEADGCF)