Let's take a look at just 3 characters the Y's. As with Hiragana, modern Japanese doesn't use Yi or Ye.
Write them out 10 times a day and soon you will get it. To aid memorization, make silly associations to go with them. You can use the above mnemonics or you can make your own!
ヤフー ____________ This
ハレルヤ____________ This means ____________
ユタ_____________ This means ____________
トヨタ _____________ This means ______________
ユース_____________ This means ______________
ヨーヨー _____________ This means ______________
Perhaps you can recognize these 5 in just one day of practice.
ヤフー yafu- This means Yahoo