Hello
You could say it's like meditation because you are focusing on purifying the Heart through worship and contemplating deeply about your Creator and reason for existence. You also have to abstain from that which is prohibited of course because that which is prohibited usually darkens the heart. I will elaborate...
Allah Most High says
"So remember Me; I will remember you"[2:152]
Mohammad(SAW) was sent by Allah Most High for 4 things as explained in this Hadith:
It is He who has sent among the unlettered a Messenger from themselves reciting to them His verses and purifying them and teaching them the Book and wisdom - although they were before in clear error [Quran 62:2]
http://www.qtafsir.com/index.php?option=com_content&task=view&id=1351&Itemid=118#2
To break this verse down it mentions Mohammad(SAW) was sent to teach the people how to
1) Recite Quran (His Verses with Tajweed and Tarteel)
2) to Purify them (Their Hearts)
3) to Teach them the Book (Tafsir of Qur'an)
4) Hadith (Wisdom)
Sufism is concerned with 2). Note the order of importance here also, after the Qur'an recitation (which also helps purify the Heart) comes the purification of the Heart before Quranic Tafsir and Hadith. There have been many hadiths for the importance of Purifying the Heart:
"Beware, in the body there is a flesh; if it is sound, the whole body is sound, and if it is corrupt, the whole body is corrupt, and behold, it is the heart."
[Bukhari and Muslim]
So if the Heart is corrupt then the mind itself will deviate from the Path. The Mind is a tool used by the Heart/core to get what it wants and it is the Heart which filters what it desires from what it reads and not the mind. So the state of the Heart is paramount to correct guidance. Sufism is concerned with actions which Purify the Heart and knowing which actions have negative affects on the Heart. As these negative affects ultimately act as a blocker to our relation with Allah Most High, stop us from deriving his blessing which leads to serenity in this life, beatific visions and paradise in the Hereafter. This is why Allah Most High says:
"He has succeeded who purifies himself" (Qur'an 87:14)