I do not understand the fascination with box mixes. It is so damn easy to measure out 2 cups of sr flour, 250g butter, 1 cup sugar, a bit less than 1 cup liquid etc. Using the same cup for all measurements. Also, for a really nice lemon cake, add the finely grated zest of a lemon to your flour and stir it in. Save the juice for making the icing. Where it really shines.
Wherever it says butter in a recipie, you can sub with marge. Even better, half marge and half lard. Lard is one of the best fats for cake making - really luscious texture and cake keeps better. Harder to mix in - best to use a stand mixer if you have one.
Butter cake is best cooked in a medium to medium/low oven for 1 hour or more. It's not a sponge where the raising agent is stiffly beaten egg white - which is best done in a hotter oven. Chocolate cake is the standard butter cake mix with 1 tablespoon of cocoa/drinking chocolate added to the flour and 1 more tablespoon of liquid.
Roll chopped fruit (any sort) in the flour mix before adding liquid. Stops the fruit from all settling at the bottom of the cake tin during baking. Works especially well with fresh cherries. And strawberries. And raspberries.
Use castor sugar not the regular white sugar - dissolves a lot faster and the cake bakes better.
You can turn regular sugar into icing sugar by whizzing it up in a food processor with the sharp blades in.
Vanilla essence is made from pine bark chips? I stopped using it entirely when I found this out. Be damned if I'll cook with mulch. Extract is the way to go. More expensive, but you use a lot less and the flavour is better.
GREASE AND LINE YOUR CAKE TINS!!!!! Olive oil spray is revolting and doesn't really do the job. Butter or marge is much better. One lump the size of an unshelled hazelnut will do most standard cake tins. For fancy, or if you want the cake to keep fresh out of the fridge, then a crust lining works well. Grease tin as per usual, then mix up 1 dessertspoon of sugar with 1 dessertspoon of flour. Tip that into the tin and tap the tin all around to distribute the mix evenly over all the surfaces of the inside of the tin. Tip out excess. This gives the cake a wonderful brown caramelized crust over all of it bar the top, and keeps the cake fresh for longer.
Cakes cool quicker if you put them upside down on the cooling rack. This also helps level the top which is handy if you don't want to cut off the top before icing.