It's easy to fixate on how much, when and what to eat. Not to mention how to prep. But it starts with the 'what to eat'. This post is a simple list to address that. Not comprehensive but simple. 100 calories of these foods give you between 30 and 100 calories of protein. That number means its easier to get to the 70-100 grams of protein that you require in a day if you increase the portions of these foods.  

YOU COULD MAKE A HABIT OF INCLUDING ONE OR TWO THESE FOODS IN EVERY MEAL: 

CHICKEN BREAST 
FISH 
SEAFOOD
MUSHROOMS 
LEAN CUTS OF MEAT 
DEFATTED NUT PRODUCTS 
SOY 
PROTEIN ISOLATES 
LOW FAT CHEESE 
COTTAGE CHEESE 
OMEGA-3 RICH FISH 
EGGS  
EGG WHITES 
PEAS
SKIM MILK

Pairing this with moderate portions of rice/millets/wheat/maida, lentils/chole/rajma/dal and vegetables will make for a complete, fuss free meal. Food selection and including a reasonable dose of protein in every meal makes things simpler on multiple fronts:
1. Takes care of the rate at which sugars are released if this something you are concerned about (and a lot of people seem to be)
2. Satiety and satiation are addressed. Satiety is a function of texture, smell and consistency of food. Satiation is purely a function of volume. Satiation ensures you are full at the end of the meal. Satiety ensures you will not feel hungry for a while after the meal. 
3. There will be enough amino acids floating around in your blood stream. You don't have to worry about rushing that shake after a workout. 
4. Picking as many sources of protein will also ensure enough of the essential amino acids your body cannot produce. Diversity and pairing of foods is crucial especially if you are on a more restrictive diet or exclude food groups for health, moral or ethical reasons.