At this point, draw a vertical line with a short horizontal near the top. To the upper left, write Indirect Object Pronouns, to the upper left, write Direct Object Pronouns. Vertically, on the left, write in descending order: me, te, nos, os (if you teach it) and se. To the left of se, draw two arrows pointing to se and write le and les at the left end of the arrow. In the right hand column for the direct object pronouns, write, in descending order lo, la, los and las.
At this point, they will wonder why se, a word they've probably only seen as a reflexive object pronoun, is doing on the list. So this is the time to tell them that besides putting the indirect object pronouns before the direct object pronouns, they need to remember that when le or les would precede any direct object beginning with the letter L, they must change le or les to se. Assure them that if it is reflexive se, they will figure it out from the verb used. Show them that Me lavo las manos > Me las lavo isn't a big stretch for the mind. If they don't use os, there are only sixteen possible combinations, using two sets of four words each.
Finally, they need to be reminded about the third person. Ask them how many grammatical persons le and les could refer to? Write Se lo doy on the board and ask them to come up with all the possible receivers or indirect objects the indirect object pronoun se could be representing. After showing them the clarifiers a él, a ella, a Ud.; a ellos, a ellas and a Uds., give a quick quiz in which they will have to identify objects of different types, subjects, and finally make progressive substitutions ending in a sentence with double object pronouns. Of course, only give them sentences with one verb.
Many students wonder if you can leave out the indirect object if you just use a clarifier. The answer is a simple no. Clarifiers are just that -- they clarify something that is already there. It is the clarifier that is optional.