This site consist of many different beliefs, so with that being said, please keep in mind that this is only mine.
I believe that spells aren't just fancy words, and potions. Spells for me help put the intent of a change into play. Yes, I think the person needs to think about the spell they casted, and use positive engery, positive thinking, as well as physical work in order to make the spell work to its fullest possibility. For example a person can't cast a spell to get their dream job, and then not go put applications, or get their name out there through contacts.
If a person is over thinking the spell, and it becomes madding, most likely it's because that lack in self confidence.
Try meditation, and positive thinking. Ask (whomever you whorship) for strength, guidance, confidence, and positive energy. Believing in magic(k) is only a part of it, you must believe in yourself too.
With that being said, over time it becomes second nature, where you do sometimes just walk away, and don't really think about the spell after. You'll still be doing your part, but it'll just come natural and appear to take less effort.
Again, this is my opinion, it's what works for me.