There is self-discipline, and then there's discipline inflicted by others. I think that autism actually makes _self_discipline better, but it has to be toward something that _you_ want, like your Special Interest. I suppose the trick is to convince yourself that you want to bring home straight As on your grade card, or whatever.
Motivation, similar. Think about what you want, and what steps are necessary to _get_ what you want.
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Asperges me, Domine