1st thing - line the tin with greasproof paper or, better still, baking parchment. Let it cool in the tin.
If you want something that just cannot fail, go for a rich fruit cake.
Making any cake, mix butter/marg with the sugar, then the eggs, then the other stuff. try not to mix too much after you've added the flour.
Making a rich fruit cake, mix flour into the fruit, fruit into the fat/sugar/egg.
Actually, I think that someone left a cake out in the rain, and I don't think that I can take it.