Start with the contrast
An ivory blazer over black creates a clear outline. The light fabric draws attention to the shoulders and lapels, while the dark outfit underneath reads as a more continuous base. In this edit, the short hem and tall boots add another contrast in proportion.
You do not need the exact pieces to try the idea. An ivory jacket over a black midi dress or black trousers gives the same light-over-dark starting point with a different silhouette.
One ivory tailored layer + a mostly black base + a deliberate shoe choice. Keep additional colours limited while you work out the proportions.
Look at the lengths together
The length of the jacket changes how it relates to the hem underneath. A longer blazer can become the main outline; a shorter jacket leaves more of the base outfit visible. Look at the whole combination in a mirror rather than choosing each piece separately.
If you use wide trousers instead, consider how their volume sits below the jacket. The goal is a silhouette you like, not a fixed rule about what a particular body should wear.
Let the shoe change the mood
Tall boots make this version feel more pronounced. A simpler low shoe would create another interpretation. For a real outfit, choose footwear that suits the surface, weather and time you expect to spend walking. Visual balance should not be the only decision.
Finish with a small detail
A small earring or a simple bag can be enough when the light-dark contrast is already strong. You might repeat the ivory in an accessory, or keep the accessories dark so the blazer remains the focus.
Before adding more, try removing one detail and compare the result. If the simpler combination gives the tailoring more room, keep it. If the extra detail expresses your style better, that is a useful answer too.