The Great Wall of Spanish

In a class I recently attended, the topic was Spanish indirect object pronouns, a heretofore difficult subject for me - and one of my fellow students spoke of her time in an immersion program in San Miguel de Allende. Her teacher there described the inability for English speakers to understand them as "The Great Wall of Spanish" - those students that got over the wall and understood how to use them, were basically on their way to full conversational fluency in Spanish. I want to climb that wall. Quiero subir aquella pared.

I'm not quite to the top yet, but I've found myself using them more, and hearing them spoken. I get it: Darme isn't some new word I haven't seen or heard before it's dar-me: give me. Puedo hacerlo! ¡Démelos, por favor! ¿Tengo que practicarlos más, verdad?

ME to/for me
TE to/for you
LE, to/for you, to/for him, to/for her
NOS, to/for us
LES, to/for upu (plural), to/for them

Verbs that require indirect object pronouns are easy to spot - if you can say "to" or "for" after the verb in English, it takes "le" in Spanish. por ejemplo:
I spoke to him: Le hablé.
I sang to her: Le canté.
I bought for him: Le compré.
However it doesn't sound right to say:
I visited to her.
I invite to him.
I kissed to her.
So these types of verbs take "lo" or "la", not "le".
I visited her: La visité.
I invite him: Lo invito.
I kissed her: la besé.

Test the verb: if you can say to/for with it, then it take LE.

Another aspect about using LE is that in Spanish you must use both the noun and the pronoun with verbs that take "le". Por ejemplo:
I wrote to my mother: Le escribé a mi madre.
Literally you are saying "To her I wrote to my mother" notice that the "a" is a personal a and not "to".
It works the same when asking a question.
¿Le compró una camisa a su primo? Did you buy a shirt for your cousin?

Things get a bit more complicated when you combine pronouns, ¿pero bastante ya, verdad?