Salam Aleikum everyone,
First let me start by congratulating all those who worked on this website, it's amazing and God bless you all for what you did. Brothers and sisters, http://www.mobda3.net is a huge calligraphy website with lots of tutorials, videos and courses. Unfortunately, it's in Arabic only. However, I will post links to some of the best material they got and try to give some English explanation with it. The website has some prominent calligraphers from Syria, Egypt and the Gulf area as active members. Example:
1- Videos of how to write the complete arabic ABC's in Taliq by calligrapher Shoukry Kharsho of Syria, president of the Arabic Calligraphy department at the Middle College of Applied Arts in Damascus.
http://www.mobda3.net/vb/showthread.php?t=10001
2- Some Niskh basic exercises by calligrapher Mohammed Amzil of Morocco.
http://www.mobda3.net/vb/showthread.php?t=217
3- Video of Niskh exercise by calligrapher Ahmad Adel of Egypt
http://www.mobda3.net/vb/showthread.php?t=745
4- Different names in different styles of the website members by the great Syrian calligrapher Adnan Al-Sheikh Othman
http://www.mobda3.net/vb/showthread.php?t=10608
5- Some explanation on the Ottoman Diwani Jali
http://www.mobda3.net/vb/showthread.php?t=7149
6- An exercise by calligrapher Mohammed Al-Maghrebi of Egypt
http://www.mobda3.net/vb/showthread.php?t=11073
7- Link to photos of amazing calligraphy and signs by no other than the great Sami Efendi may Allah bless his soul. http://www.mobda3.net/vb/showthread.php?t=3
8- Video of how to cut the bamboo pen by calligrapher Ahmad Arakeeb of Egypt (5 min)
http://www.mobda3.net/vb/showthread.php?t=289
9- Video of tips on how to do calligraphy using a painting brush by calligrapher Ahmad Arakeeb of Egypt
http://www.mobda3.net/vb/showthread.php?t=557