No one has really addressed your first question.

If you are really determined to minimize costs, you will need to forget about your loyalty to one program or carrier and just buy the cheapest ticket every time.

There are no special days of the week on which or special times at which to buy tickets, though some self-described "travel experts" may claim otherwise. You just need to buy tickets in advance (i.e, more than three weeks beforehand) using a price comparison site.

However you will probably soon find that some airlines are particularly bad (no alcohol on some, no in-flight entertainment on others, for instance) and others more tolerable.

If you get Silver I think the airport experience becomes much less stressful principally because, for the most part, you can skip a lot of queues. Also the free wine in the lounge probably helps ...