Let's take a look at the H's. What you would expect to be 'HU' is usually pronounced 'FU'
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!
ハニー ____________ This
ヒット ____________ This means ____________
ファン_____________ This means ____________ ( ン is the katakana nasal or "n" )
ヘア _____________ This means ______________
ホテル _____________ This means ______________ (ル is the katakana for ru)