Place a block of Obsidian above your head to minimize taking massive knockback from your own TNT.
Ignite the TNT and wait approximately 3 seconds (or until the 7th-8th white blink) before jumping. TNT Jump
Practice placing the TNT while running forward, aiming for a consistent jump-run-place rhythm to avoid falling into your own trap. 4. Advanced/Creative Methods Place a block of Obsidian above your head