Qiāntóuwànxù de wèntí, bìxū yí jiàn yí jiàn jiějué.
Myriad complicated issues must be handled one at a time.
Tips
history
From Cao Zhi's Three Kingdoms-era essay 《自试令》: 千端万绪 — the variant with 端 (ends) rather than 头 (heads) is the earliest form. The metaphor is silk threads — 绪 originally means 'end of a silk thread' — implying many tangled strands to unwind.
memory
Picture a ball of yarn with a thousand ends sticking out. 绪 = 'thread-end' (the 纟 radical is 'silk'). Pull any one and more tangle up.