Re: Gaining Strength - Just crossfit?
Like many said before in this thread and many other thread
Eat more (add lot of avocado, bacon, olive oil, sweet potatoes and animal protein),
lift heavy, reduce length and increase weight of metcons (many program available you can follow)
Learn to optimise rest and sleep. There is a lot of litterature available on that topic read and experiment what works best for you
There is no special secret, eat, lift heavy and rest