The phrase "to hook the reader" means to capture or grab the reader's attention right from the beginning and make them interested in reading more. Full definition
It seems to work to hook the reader in from the very beginning. (bookbrowse.com)
My workshops have always focused on hooking readers with craft elements taught to me by literary masters. (marlamiller.com)
Use these formatting techniques only once or twice to really hook the reader into reading the most important information, which will inspire them to read on. (dummies.com)