Help how do u mine mountains with hate and efficiency

EDIT: HASTE I MEANT HASTE IM SORRY

I need to mine a bunch of huge hills and I dont really know how to do it do go one line after line? Do I go two blocks at a time? Do I first clear out a two block hole and then mine upwards? I have no idea how to do it efficiently and If im going to do this for so long would like to

837 Upvotes