Warm undertone - Consider rich & warm shades like golden blonde, rich reds, chestnut brown.
Cool undertone - Consider ash tone or burgundy (deep reddish-brown shade).
Going too dark can create an unnatural contrast, while too light can wash out your complexion.
Use color-safe products, stay away from UV rays, moisturize the scalp & hair & maintain regular trim.
Try temporary colors such as rinses & spray to see how you feel about new shades.
The best option is to get personalized advice from hair stylists who will assess your hair type, texture, and condition.
Select shades close to your natural color for easier upkeep. This can save you time and effort.