Learn Russian: Суд не принял это обвинение.

While the 'Genitive of Negation' is common, it is not a strict rule. Using the Accusative case here (это обвинение) emphasizes that the court rejected this specific, concrete charge. Words like это (this) make the object definite, which strongly favors the Accusative. If the sentence was 'The court didn't accept any charge,' you would be much more likely to see the Genitive (никакого обвинения).

Where does the stress fall on принял, and does it change in other genders?

The stress is on the first syllable: при́нял. This is a tricky verb because the stress shifts depending on the gender in the past tense. For masculine, neuter, and plural, the stress is on the prefix (при́нял, при́няло, при́няли). But for the feminine form, it jumps to the ending: приняла́.

Why use the perfective verb принял with не instead of the imperfective принимал?

Using the perfective не принял simply states a factual result: the action of accepting failed to happen on this specific occasion. If you used the imperfective не принимал, it would imply a habitual action ('the court doesn't usually accept'), a continuous process ('was not accepting'), or that the court didn't even consider the charge in the first place.

How can I break down the word обвинение to remember it better?