"I have made a tincture before but I think it was too high in THC. Do I need to use a specific strain or can it be a specific method as to how I get the high ratio of CBD to low ratio of THC? "
You would need to use a specific strain that is high in CBD and low in THC, There are some out there like AC/DC, Harlequin and many more. Take some time to look at the different strains, one website I like to use is www.leafly.com. Here is an article that might be helpful to you