When I set out to learn the night sky (still a work in progress), I had a think about how to do it. What I came up with was to memorize the order of the zodiacal constellations, starting with Pisces and ending with Aquarius. I reasoned that no matter what time of year I went out, at least three of these should be visible. So these are:
Pisces, Aries, Taurus
Gemini, Cancer, Leo
Virgo, Libra, Scorpius
Sagittarius, Capricornus, Aquarius
I repeated these to myself many times during the day until I had their order memorized then set about translating theory into practice - finding key stars in the night sky that would help me identify them. This became the foundation I would build on.
Next were the circumpolar constellations, again always up in the sky (at my latitude, at least). From there, the others were/are piecemeal, learning small tricks to find them. For example, as silly as it must sound, I kept getting the head of Draco mixed up with the keystone of Hercules, getting me into much difficulty in locating M13. Then someone taught me the 'Deneb to Vega and same distance again' trick and now I can find it effortlessly. It's the smaller, dimmer constellations that get me now, but they too will come in time.
Iteration is the key - starting small and building from there, layer after layer, until they become old friends. There's also a great app on Android that helps - Sky Academy - that teaches the constellations first with full lines and borders, then with just borders, and finally with just the stars themselves, at all orientations as you would see them during a year.
Just my perspective, others will no doubt have a different experience.