The Towers are open late some evenings, which many people either don't know about, or don't think of going later in the day as everyone always says " go first thing to avoid lines" . The line watcher told up the evening were usaully very quiet, so go about 5 and see how lines are then.
The line for the church is never that bad because although it may look long, it moves constantly you do not pay to enter so people just shuffle along slowly.
Lines at Lourve, avoid by entering by metro entrance or underground shopping mall( enter off Rue Du Rivoli, under an awning that says shopping or some such thing( I can't remember but I knew it when I saw it) you go downstairs buy ticket from machines and basically walk in( after waiting 10 minutes to go through security) I have done this numerous times, in July and August. Don't bother with Pryamid entrance , lines tend to form there most often.