I normally marinade the chicken in yoghurt mixed with 1tablesp cumin, 1teasp coriander, 1tablesp garam massala, some lemon juice, 6 cloves garlic and 1`inch(about 2 teaspoons) ginger, you make the marinade and put the chicken in it in the fridge for between 2-24 hours, then cook at the highest heat your oven goes for about 20 minutes.
That gives you the tikka chicken, then you can either use it by itself or chuck it in the massala. I have to admit with garlic I'm bloody lazy and I ahvent got round to getting a garlic crusher yet (after 8years of playing house blush) so I often use garlic powder or dried garlic.
For a nice quick curry sauce (massala) take a tin of sieved toms or some passata, and add one chopped fried onion, 2teaspoon curry powder 1/2 tsp chili, 1 clove garlic either 3 inches of grated ginger or about four teaspoons of ground ginger, 4 teaspoons coriander leaves and 1 teaspoon garam massla, 2tablespoons of plain yoghurt and a dash of cream.
There, c&p'd from another thread as i'm typing one-handed!