plough on
To move, progress, or develop at a slow but constant and deliberate pace, especially that which is menial, time consuming, or tedious. Primarily heard in UK. John: "Hey Steve, what's new?" Steve: "Nothing much, just been ploughing on with research for my thesis." A: "I've still got a ways to go before I'll be finished clearing out debris from the property." B: "Well, just keep ploughing on until you're done!"
plow the sands
To do something that seems futile. I know that I'm just plowing the sands by telling you to stay away from that boy, but I'm your father, and I don't want to see you get hurt. That couch will never fit up the steps—tell them to stop plowing the sands!