Korean language school is obviously the best choice, but this option is both expensive and intensive. For those with less money and/or time, making Korean friends is a really good option as well. Try practicing you Korean with every opportunity you get and feel no shame or embarrassment when you get a spelling, grammar or pronunciation wrong.
Memrise (or ANKI)
Memrise is an online learning tool which uses spaced repetition and mnemonics in order to help your learn most effectively. That means it automatically spaces out word practice over longer and longer intervals of time so you don’t see the words too often, nor wait so long that you completely forget them while you practice. It also means you get to use mnemonic devices which are created by the community which considerably saves you time when recalling words.
For more information, click here.