How to work out calorie intake??

Almost all food has the calories and macros on the label these days, it's just a case of sitting down and doing the sums - it's dull but doesnt take too long.
If you want to add up how much you're getting from individual macros you can do that aswell but obviously takes quite a bit longer.
I get withering looks from my wife whilst surrounded by tins and packets etc.

nutritional info on generic food like eggs etc can be found on t'internet - just google it.
I tried doing it all on the internet but it worked out alot quicker just to get the packets themselves.

Protein and carbs have 4 calories per gram.

Fat has 9 calories per gram.

It's a good idea. I used an excel spreadsheet.

At the very least you gives you an understanding of what you're putting in your body

I found that after two months of keeping a meticulous record I could pretty much tell what was good or bad for me, which was something I never really paid attention to before.

Here's some resources:

http://www.nutritiondata.com
http://www.calorie-count.com/