Besides mistakes in the content of your documentation, there are two kinds of mistake you can make with Texinfo: you can make mistakes with @-commands, and you can make mistakes with the structure of the nodes and chapters.
Emacs has two tools for catching the @-command mistakes and two for catching structuring mistakes.
For finding problems with @-commands, you can run TeX or a region formatting command on the region that has a problem; indeed, you can run these commands on each region as you write it.
For finding problems with the structure of nodes and chapters, you can use
C-c C-s (texinfo-show-structure) and the related occur
command and you can use the M-x Info-validate command.