Let's take a look at the T's. You may want to make flashcards to practice by.
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!
テスト ____________ This
アイス ____________ This means ____________
コート _____________ This means ____________
アート _____________ This means