If this card is in your hand, use "Card Trader" or any other card that could shuffle this card back into the Deck, since "Assault Mode Activate" only Special Summons the "/Assault Mode" monster from the Deck.
Use "Dragon's Rage" with this card for piercing damage, since this card destroys every other monster than itself, it won't allow you to follow up on a defenseless opponent by attacking with a second monster and thus it will actually be harder for you to do damage with this card.
If you somehow get "Neos Wiseman" out along with this card, you can get an additional attack because "Neos Wiseman" cannot be destroyed by card effects.
If you manage to get two copies of this card out, when the first one attacks, it will destroy the second one, allowing you to revive "Red Dragon Archfiend", allowing for another attack.
If you have another monster(s) other than this card that you want to attack with, make sure that you attack with that/those monster(s) so you may at least destroy monsters by battle or inflict battle damage to your opponent other than this card.
Consider using this card is conjunction "Final Attack Orders" if you want to damage the opponent, seeing as your other monsters will be destroyed after this card is done with its attack.
If you have this card on your field when you clear the field, with a card like "Black Rose Dragon", you'll both clear the field and attack your opponent's life points directly with the non-"/Assault Mode" version of this card.
You can use this card in a "Fortune Lady" deck. When this card clears the field and destroys your "Fortune Lady Light", you can Special Summon a "Fortune Lady Dark" and attack your opponent directly. If your opponent happens to destroy your monsters with cards like "Mirror Force", you can Special Summon "Red Dragon Archfiend" and still attack.
You can combo this card with "Stardust Dragon/Assault Mode" to create an OTK First Summon "Stardust Dragon/Assault Mode" and then Summon this card; first, attack with "Stardust Dragon/Assault Mode", then attack with this card, and then negate the second effect with "Stardust Dragon/Assault Mode" and then Special Summon "Red Dragon Archfiend" do a last attack to make a 9500 Battle Damage.