Shaykh ‘Abdullah ibn ‘Abdil-‘Aziz ibn ‘Aqil (rahimahullah) said:

There are six matters by which we can discern that an Imam possesses understanding (Fiqh) of the rulings of the prayer:

The first: The Imam should shorten the pronunciation of the opening takbir and not extend it, whether when pronouncing “Allāh” or “Akbar,” although extending ‘Akbar’ is worse^[1]. The Imam should not prolong it because if those praying behind him precede the Imam in takbir (by saying Allahu Akbar before the Imam finishes saying it), their prayer will be invalid, and similarly, if the Imam coincides with them in saying it, according to the opinion of some scholars. Likewise, he should not extend any of the takbirat to prevent those praying behind him from preceding him.

The second: The Imam should shorten the pronunciation of the taslim and not extend it to prevent those praying behind him from hastening before the completion of the Imam’s taslim (by saying ‘as-salamu ‘alaykum wa rahmatullah’ before the Imam finishes saying it).

The third: The Imam should shorten the sitting of the first tashahhud as it was narrated in the hadith that the Prophet would sit in the tashahhud as if he was sitting on a hot stone (Abu Dawud no. 995).

The fourth: The Imam should not pray within a mihrab in a way that he is concealed from the view of those praying behind him.

The fifth: The Imam should pray near the first row and not leave a gap between himself and the first row except for what is necessary, ensuring that his feet do not touch the heads of those behind him. Similarly, the other rows should be close to each other.

The sixth: When reciting Surah al-Fatihah in the loud prayers, he should stop at the end of each verse. Surah al-Fatihah has seven verses, so he should pause after each verse and avoid reading two or three verses in one go.

Source: Kashkul Ibn ‘Aqil (pg. 12)

Read: Biography of Shaykh Abdullah ibn Aqil and Some Benefits from His Lessons — Ustadh Mustafa George

Footnotes:

[1] When saying ‘Allahu Akbar’, the word ‘Allah’ should be stretched for two counts as ‘Allaahu’. The Shaykh advises the Imam against stretching it longer, such as ‘Allaaaaahu’, which some Imams do mistakenly. Regarding ‘Akbar’, it should not be stretched at all. Therefore, if the Imam says ‘Akbaar’, it is considered a major mistake.