Once you get to light 290 raids really are the way to go to get your light to 300, as you can get 300+ light weapons and equipment that will quickly push you up to light 300 and beyond (as well as letting you get a 310 artifact through doing a quest from completing the raid). Once you reach light 300, any exotic engrams you decrypt (from Xur or using 3 of coins) have a chance to come out as 310 light armour/weapons (as well as 290, which they can still decrypt at), which can then be either equipped or infused into legendaries. Better to get past light 300 before going infusion mad, in my experience. You won't know what you'll want to keep until then.
Also once you are light 290 you are easily good enough to take on the entire raid.