Until spring 2013 Assad was rapidly losing ground. Then he managed to stop.
There are several factors why it happened:
1) Assad does not have enough troops to control the entire country. But when his territory shrank the defence for him became much easier.
2) First Assad was somewhat reluctant to make massive war crimes. But then he realized that no one gives a damn. Assad began to use massive barrel bombings, heavy "Vulcano" rockets, starving blockade, ethnic cleansing. He even used chemical weapons once, but then world finally reacted.
3) Hezbollah and Iraqis Shias arrived to help him.
4) Russia and Iran increased help to Assad sending regular supplies.
5) ISIS attacked rebels and Kurds.
So here are Assad's achievements in 1 year:
1) He stopped losing ground in massive way.
2) With help of Hezbollah and heavy bombings managed to cleanse some encircled rebel enclaves in Homs and Qalamoun.
3) In Damascus using starvation and barrel bombs he forced several rebel areas to sign truce. But this truce is not surrender and it can also act in both ways, because rebels from other areas can get supplies now from "truce" areas.
Does it mean that Assad is winning? - Nope.
1) North-East of the country, where are located virtually all Syria's resources dont show any improvement. Rather on contrary.
2) The situation in south of the country became considerably worth for Assad.
Rebel brigades became much more mature in this year. They started production of own artillery (hell cannons and mortars). They received some ATGMs.
Whats going to happen next?
If the situation is not changing (Assad receives massive aid from Russia and Iran, Hezbollah, rebel receive ATGMs) then the situation will not change much either. Assad may finish two remaining enclaves in Homs (Homs old city and the triangle Talbise-Rastan-Houla). If rebels receive more supplies (lots of ATGM, mortars, some MANPADS) then Assad will begin losing ground again.
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Anyway, Assads economy is destroyed for good, he cant survive anymore without billions of annual aid from Russia and Iran. Basically only prolonging his agony.