Avoid deciding the object from position or one visible ending alone.
1. Do not reverse fa'il and maf'ul bihi: in ضَرَبَ حَامِدٌ مَحْمُودًا, Hamid acted and Mahmud received the action.
2. Do not demand a separate fa'il noun: نَصَرَ الْمُسْلِمِينَ has an understood fa'il.
3. Do not demand fathah on every object: الْمُسْلِمِينَ uses ya and السَّمَاوَاتِ uses kasrah.
Meaning establishes the relationship; the appropriate case sign confirms it.