If I wake up midflight I just think "No, no, **** this, no, absolutely not, fall back asleep," over and over until I do. If it doesn't work I just read my Nook for like 20 minutes and then try again.
The trick is to not use your phone/DS/PSP/iPod or anything with a backlit screen, because that will force your brain into "awake" mode. It also helps to travel early in the morning or in the evening, because they'll keep the plane dimly lit.
Always try to fly our national carrier or one of their subsidiaries (i.e Jetstar, Air Pacific) whenever I can. Just flew back from Mildura with Qantas Link last week. The flight was great. Luggage, food & a beverage service was all included in the fare as well which was great. Will always try to choose them over other carries if I can. Price doesn't really concern me anymore really.