I'm guessing you're new in Doha:
1) Deccan Deewan on Salwa Road exactly under Midmac Roundabout - great Hyderabadi cuisine
2) Broast BBQ on Matar Qadeem Street - again good non veg Indian/Pakistani menu
3) Qutba Restaurant in Mansoura is Pakistani but should definitely be tried
4) Star of India restaurant on TV roundabout - a long term favourite for many people, although I haven't been there in a while.
5) Star Restaurant - this is a slightly off beat place and serves all kinds of stuff - Arabic, Indian and others - near New World Center and Bank Street.
6) If you are vegetarian (i hope not haha), you have Saravana Bhavan right next to the 5th restaurant - and another good one on Crazy Signal.
7) Asiana is also a popular place - both in Al Sadd next to Family/Food Mart and in Muntazah behind Al Meera.
There are many more places and you'll find them as time goes by:-)