请教一下开手动档的高手们

该如何平滑的从1档换到2档? 我现在十次只能有1-2次换的好, 其他时候总是能感到抖动. 我都有点搞不清是换早了还是晚了.

Transmission gear ratio (1st) 3.77
Transmission gear ratio (2nd) 2.04
Transmission gear ratio (3rd) 1.37
Transmission gear ratio (4th) 1.05
Transmission gear ratio (5th) .85
Transmission gear ratio (6th) .71