you can't do nothing, there is no profit in bitcoin, not for casual miner at least, and if you have free electricity you can't touch roi, sad days for any miners
I would not say that. If you have low electricity and space it's still possible. There is always hosting aswell.
Do ROI on your estimates. Do some with good and some with bad difficulty changes. You will see this way how many months, or what network difficulty is needed for you to profit. And it will also show if your in someplace with VAT and high electricity that will add on to it.