When i do cakes I use Jacqui's mix who used to be on here, before sockville days!
Weigh my eggs, and use same in caster sugar, stork and self raising flour, drop of vanilla extract and teaspoon of baking powder, although i am heavy handed with the baking powder! but they always come out dead flufy and light, and taste yummy!
She always told me to electic whisk the caster sugar and butter first for a good 5-10 mins, then add the flour and eggs half at a time, so it all mixes in well
I use a 5/6 mix for splitting between the 2 8inch cake tins, hth though im a novice!