When my baby is still young, I used dental wipes for baby such as the brand 'ToothTissue" or Spiffies. 'ToothTissue" is N.P.A. certified, natural, fluoride-free, paraben-free, and contain xylitol. It is recommended that we can clean baby using dental wipes even before the teething to help teeth grow healthily. When baby is older, I use pigeon steps brush (3 steps). Make the brushing a fun activity by singing song.
I do not brush their gums as I afraid that it will irritate the gums. I just use boiled water and wash cloth to clean his mouth, tongue and gums. Even till now his first tooth had emerged I'm still using wash cloth to clean.