al-Taqarrub ila-Llah

Imam al-Nawawi (d.676/1277), may Allah be pleased with him, mentions in his al-Maqasid that among actions that will draw one closer to Allah, The Exalted are the followings:

[1] Making repentance (tawba) from all actions, be them blameworthy (makruh) or forbidden (haram);
[2] Seeking sacred knowledge: knowledge of the Hereafter;
[3] Maintaining ritual purity always: (wudhu');
[4] Perfoming obligatory prayers in the first of their time and with congregation;
[5] Performing sunna prayers correspond to each obligatory prayer;
[6] Performing 8 rak'at of Dhuha;
[7] Perfoming 6 rak'at of nawafil prayer after Solat Maghrib;
[8] Tahajjud;
[9] Witr;
[10]Fasting on Mondays and Thursdays, and 3 days of full moon (13th,14th,1 5th Hijri month)
[11] Reciting al-Qur'an with the presence of the heart;
[12] Making istighfar;
[13] Making Salawat to the Prophet Sallallahu alayhi wassalam
[14] Zikr mornings and evenings

May ALlah give us strength and with His Tawfiq accepts us to be among the closest (al-muqarrabin) of his His servants, Ameen.

And ALlah knows best