Measuring

Weight
When measuring in weights decide to use either pounds and ounces or grams and kilograms don't mix them. Baking is about ratios and changing measurements can skew those ratios (there are 28g in an oz but many recipes round it off to 25g or 30g)

Scales
You will need a scales when you're baking. It doesn't need to be very extravagant. I bought a cheap digital one years ago and I like the simplicity and accuracy it provides, others swear by the admittedly more elegant traditional scales.

Spoons
Spoons used for eating or drinking with have different sizes so its worth buying a measuring spoon. A measuring spoon is a keyring with a series of spoons on it ranging in size from Tablespoon to 1/4 tsp. They don't cost a lot. Unless a recipe specifically calls for a heaped spoonful of something you just want the measure of what is in the spoon.

Cups
When a recipe calls for a cup it usually means an American this is about half of a mug in capacity and when I say mug I mean those standard sized ones that you get with worlds best Dad on them etc. Similar to the measuring spoon you can buy the cup measures on a keyring.

Conversion Table
There is a universal converter on the blog but here is a link to Delia's conversion table which is quite useful especially if you don't have all the measuring cups etc.