Here's one of the reviews I found there:
...although I am not as well-read in this sub-genre as would be ideal to make recommendations, I can say that from the first few pages of Rosarito Beach I was struck with the impression of a clear similarity between Lawson's style and that of Janet Evanovich.
Dear reader, that funny sound you hear is me dropping my teeth with surprise. Janet Evanovich?!?! Now, make no mistake about it: I love the Stephanie Plum novels and I think Janet Evanovich is a terrific writer. But let's think about this a bit:
Stephanie Plum is competent only by accident. She's deeply involved in her family, as her family is with her (Grandma, anybody!)
More to the point, the Plum novels are written in first person, set almost exclusively in New Jersey, and the resolution of the plot is never in doubt. These novels are fresh, and fun, and lighthearted.
Contrast that with M.A. Lawson's Kay Hooper who is a DEA agent in Los Angeles. She's frighteningly competent, highly skilled, has no family to speak of and doesn't need Ranger or Morelli to save her from anyone. The book is in third person, ranges widely geographically and there's tension galore. The outcome is always in doubt. This novel is hardly lighthearted and fun, but it sure was good to read.
The point I'm slithering toward making here is that when you want to compare your manuscript to a published book in your query letter to give the reading agent a sense of where your book will fit in its category, you must be able to answer WHY the book is comparable.
When you tell me that your manuscript will appeal to readers of Dana Haynes ICE COLD KILL you should be able to tell me why. Is it third person, multiple POV? Is it a thriller? Does the action unfold over a short period of time, and in places around the world? Does the main character solve her own problems rather than relying on others? Does she carry a stun gun in her stocking?
You might not list all these things in your query (it's better if you don't) but you need to KNOW them.
The reason you need to think about this carefully is that you might surprise yourself and discover the books aren't comparable at all.
The last thing you want is me expecting fresh, fun and lighthearted and getting tense, dramatic and terrifying.
Any questions? Post to the comment column below.