Think of it like a mosaic. Each book is a beautiful, complete tile. If you look at them one by one in any order, you appreciate each picture. If you step back and look at them in sequence, you see the larger, interconnected artwork. Both perspectives are valid and rewarding. Your first time through, you might focus on the individual tiles. On a re-read, you might appreciate the bigger picture. There's no single correct way to view a mosaic.
I think the internal timeline is actually kind of jumbled. Events from 'The Proposal' are referenced in 'The Wedding Date' as if they happened before, even though 'The Wedding Date' was published first. So a true 'chronological' order of events within the universe might differ from publication order. That's why most fans just stick with publication order—it's the order the author intended us to meet these characters, even if their stories within the world overlap and intertwine in complex ways.
My friend told me to read them in order of 'holiday spirit'. She swears 'Royal Holiday' (Christmas) is a perfect starter, then 'The Wedding Date' (New Year's), and so on. It’s a bonkers order, but she loved the seasonal progression.
Not the most practical for character following, but it highlights how Guillory uses holidays and celebrations as backdrops for romance. It’s a fun, alternative thematic order if you’re feeling playful.
I view them like episodes of a great TV show with an ensemble cast. Each episode (book) focuses on a new main couple, but background characters from previous episodes pop in. Watching (reading) in production order lets you recognize everyone. Skipping around might mean missing a fun 'hey, it's that character!' moment, but you'll still understand the main plot.
If you're planning to buy them, consider the cost. Sometimes older paperbacks are cheaper. 'Royal Holiday' (2019) might be more discounted than 'While We Were Dating' (2021). Your order could be dictated by your budget, starting with the most affordable to see if you like her style.
There's no shame in a practical, financial approach to reading order. If you love the first one you buy, you'll happily invest in the others. If you don't, you saved some money. Start with the one you can get for the best price or from your library most easily.