This layout is by Guest scrapbooker for October, Karelyn
Sometimes, a page just clicks and goes together, you find the right colours straight away, or the design just happens!
The blues of the October 2021 scrapbox kit work perfectly with these photos in a 2 colour scheme, just showing a hint of 'beach' colour to offset the blues. The beautiful travel themed/driftwood effect papers from the October Scrapbox help create the feel too....
I often use a colour wheel if I'm stuck on colour choice, this combination of colours would be labelled as complementary (having 2 hues).
Complementary colour schemes can produce strong contrast on your page, giving a feeling of energy and vibrancy.
Alternatively, you can use them to tone it down a little like this layout, by using one main colour and an accent colour.