what i usually do is disassemble the joint/limb/part/whatever as much as I can. G1's are good for this as they can pretty much be fully pulled apart. use some of the 'thin' runny style of super glue (not the gel non-drip stuff) and carefully apply a tiny amount to mating surfaces. use a toothpick to spread it if needs be. effectivly all you're attempting to do is PAINT the surfaces with superglue. give it plenty of time to dry too before putting it all back together.
i'm sure there are other methods - this is just what i do.
hope it helps.