Create your own layer "meta-my-layer", inside
meta-my-layer/conf/layer.conf
set
LAYERDEPENDS_meta-my-layer = "clayer"
BBFILE_PRIORITY_meta-my-layer = "100"
#Could be any number higher than the one in meta-clayer/conf/layer.conf
create your own distro in conf/distro/include/mydistro.conf
copy paste the distro of meta-clayer inside it and do your own modification.
Do not forget to update your DISTRO variable in conf/local.conf.
An other way would be to override "settings" in your local.conf file which is the file with the higher priority but this is really not advised and not the best practice.