Don't be picky. GO where the deals are. It will only save you money to travel to more places.
Google flights allows you to check out prices for anywhere in the world and shows you the cheapest dates. If the Azores are only $500, why not choose that over $1000 to Italy?
Plan to book your flight 3-4 months in advance of leaving.
Monitor highs and lows of your flight throughout the week. Keep a note of it and book when you feel comfortable that you are receiving the best rate.
Delete your COOKIES (on your computer). If you're continuously looking at the same flight, airlines will know you are interested and you may see the price magically go up.