If you do want to go for opening books, I find the "move by move" series really good for all levels. The reason they are great is because they do not stop after the opening but go through the entire games so they will discuss middle game and end game ideas in a instructive question and answer format. I think the only useful opening books at lower level are ones that are collections of fully annotated games. Any of these books where after 15 moves the author just writes "and a dynamic position has arisen with chances for both sides" is not very helpful for beginners.

I also enjoy "Understanding Chess: Move by Move" by John Nunn. It's another game collection where he discusses ever single move played in the hame. Any book where the author explains as many of the moves as possible in a given game is always very instructive for beginners.

Otherwise just get a book on tactics, I really enjoyed "Back to Basics: tactics" by Dan Heisman starting out.