Use delo gold oil, change the fuel filter after every 10k kms, Always give it a min to warm up before departing.
Get the filters changed, there is no tune up for diesel engines 
I would not recommend the 3s stealership, because they would rip you off and then when the time comes that they get stuck, they would say that since we didn't sell this model, we can't fully fix it or lack the tools/parts for it.
Best to go to a trustworthy mechanic. If you have one, cool,if not, go to Darwaish autos in Chor chowk, besides the china hospital. They work honestly, cheaply and reliably.