Hexagram 54, Guī Mèi (The Marrying Maiden): Line 1
归妹卦初九 · 雷泽归妹 · 中文版
初九：归妹以娣，跛能履，征吉。
The line (Legge)
The first NINE, undivided, shows the younger sister married off in a position ancillary to the real wife. (It suggests the idea of) a person lame on one leg who yet manages to tramp along. Going forward will be fortunate.
Small Image commentary
'The younger sister is married off in a position ancillary to that of the real wife:' - it is the constant practice (for such a case). 'Lame on one leg, she is able to tramp along:' - she can render helpful service.
象曰：归妹以娣，以恒也。跛能履，吉相承也。
In plain words
The marrying maiden goes as a secondary wife; like the lame who can still walk, setting out brings good fortune. In ancient times a younger sister went with a bride as a secondary wife. The first line is strong and low; though not the principal wife, it does its part. The Small Image says this is the constant way, and walking though lame is fortunate because they support each other.
Applying it to your situation
If you are in a supporting role, this line suggests doing your part well can still get things done. What can you bring to a supporting role?
Position
A solid (yang) line in the first place, which is a yang (odd) place, so it is in its proper place. Its partner is line 4; both are yang, so they do not respond.
If this line moves
With this line moving alone, Guī Mèi changes into Hexagram 40 Xiè (Deliverance). The Jiaoshi Yilin verse for this change (Chinese): 焦氏易林·归妹之解.
The hexagram
Hexagram 54 Guī Mèi (The Marrying Maiden). The Judgment: Gui Mei indicates that (under the conditions which it denotes) action will be evil, and in no wise advantageous.
Next: Line 2
English text: James Legge, The Yi King (Sacred Books of the East, vol. 16, 1882), public domain, as transcribed by the Chinese Text Project. Chinese: the received text. Offered for study and reflection, not as prediction. Plain-English readings and position notes by this site.