I do something like this sometimes:
Lua Code:
local myFrame = CreateFrame("Frame", nil, UIParent) --this frame has no global name, only a local reference
myFrame.label = myFrame:CreateFontString(......)
Then, if that child will be accessed more than once, I'll assign it to a local variable for faster lookups.
Lua Code:
local myLabel = myFrame.label
myLabel:SetPoint("CENTER")
myLabel:SetText("Some text.")