Recognize a maf'ul mutlaq by form, connection and purpose.
1. Find the verb and its action.
2. Look for a mansub verbal noun connected to that action.
3. Decide whether it emphasizes, describes or counts the action.
4. Keep it separate from the person or thing receiving the action.
In قَرَأْتُ الرِّسَالَةَ قِرَاءَةً وَاحِدَةً, الرِّسَالَةَ is what was read, while قِرَاءَةً وَاحِدَةً counts the reading.