1. First confirm that the ending functions as a feminine marker; spelling alone is not enough.
2. If such a feminine form ends in ى with fathah immediately before it, identify the maqsurah form.
3. If such a feminine form ends in اء, identify the mamdudah form.
4. Do not call every feminine word one of these two forms; فَاطِمَةُ uses ta marbutah instead.
5. Then, where required, compare the word with a listed weight such as فُعْلَى or فَعْلَاءُ.
First confirm that the ending functions as a feminine marker; then name its written form.