The story goes that business consultant Ivy Lee created a simple productivity hack for Charles Schwab and his corporate executives in 1918. It is ridiculously simple.
At the end of each day write down a list of your six most important things you need to work on tomorrow. Order the list by priority importance. Concentrate on the first task until completed and before moving to the next item on the list. Repeat each day.
It is likely going to be hard to commit to only six items and then to work on just one item at a time, but if you have too many to do items, you will likely not commit to completing them or at least not promptly.