Be wary of using this card. Although it will always return to the top of the Deck when it is destroyed, it uses up your normal draw during your Draw Phase.
If this card is destroyed during your turn, you can use the effect of "Sunlight Unicorn" to avoid this.
On the bright side, if this card is destroyed during or after the turn you activate it, you can prevent yourself from decking out. Use cards like Spirit monsters to help achieve this.
Use cards like "Upstart Goblin", "Jar of Greed", "Skelengel", or any other cards that allow you to draw a card to recover it quickly so it won't hamper your regular draw during the Draw Phase.
When this card is on top of your deck, use "Jar of Avarice" to shuffle five other cards into your deck during your opponent's turn, which will displace "Horn of the Unicorn" from the top of the deck, freeing your normal draw from it and giving you an extra card upon "Jar of Avarice's" effect.
Use this card alongside "Obnoxious Celtic Guard", boosting its ATK and DEF to help it survive monsters with less that 1900 ATK, making it extremely difficult to get rid of without using Spell/Trap/Monster destruction cards.