Low-hanging Fruit

I began dipping my toes into … . I started with some low-hanging fruit. (Myers, Raising Them, p.63)

dip one’s toes into

To dip one’s toes into something is a common metaphorical expression meaning to carefully start something new without too much risk. This derives from the situation of checking the temperature of hot water using only your toes. In general, this is often used to simply mean “to start something new.”

low-hanging fruit

Something that is easy to obtain, achieve, or take advantage of. It’s easy to associate this meaning with fruits that grow on the lower parts of trees. Some people use it in the context of business or sex. You could say “high-hanging fruit” and it would probably make sense, but it is not a common expression.