Overall Fire Fists are a well-rounded deck with great synergy with each other. They work as a control deck with their Fire Formation cards as support, providing them with small attack boosts that stack up and are used as cost for Fire Fist monster's effects. Fire Fist monsters are only decent low-leveled beaters but when facing high-leveled monsters they also have effects that let them attack over them. Use the Balance skill so that you will always open with monsters and some support.
With Brotherhood of the Fire Fist - Rhino your Fire Fist monsters would be able to attack over anything, provided that you have a Fire Formation card on the field and a Fire Fist monster in your hand to use as cost. Since this effect could be costly, you can use it to boost Brotherhood of the Fire Fist - Gorilla's attack while he is in battle and then search out another Fire Formation spell after he destroys the opponent's monster. The Fire Fist monster sent to the graveyard with Brotherhood of the Fire Fist - Rhino's effect can then be revived by Brotherhood of the Fire Fist - Dragon to swarm the field.
If you activate a Fire Formation spell while Brotherhood of the Fire Fist - Dragon is face-up on the field, You get to search and set a Fire Formation trap card from your deck. A good search target would be Fire Formation - Tenken which can be activated during your opponent's main phase to protect your Fire Fist monster from their effects. Fire Formation - Tenken will also give your monsters an additional 300 attack. And when it has outlived it's usefulness can be sent to the graveyard as cost for Brotherhood of the Fire Fist - Dragon's revival effect or Brotherhood of the Fire Fist - Rhino's attack boost effect. Brotherhood of the Fire Fist - Dragon also has a revival effect which you can use to bring back Fire Fist monsters in your graveyard, particularly ones you sent to the graveyard with Brotherhood of the Fire Fist - Rhino.
Brotherhood of the Fire Fist - Gorilla can search out any of your Fire Formation spells to support your Fire Fist monsters whenever he destroys an opponent's monster by battle. The downside is that instead of adding them to the hand, they are set on the field which could make them vulnerable to destruction until your next turn. Most of the time the first Fire Formation spell you would want to search is Fire Formation - Tensu to give you swarming capabilities. You can search a Fire Formation spell card, summon Brotherhood of the Fire Fist - Dragon the next turn then activate the searched Fire Formation spell to search a Fire Formation Trap with Brotherhood of the Fire Fist - Dragon's effect. You can send 1 Fire Formation spell card to the graveyard to destroy a spell/trap card your opponent controls, usually you would use Fire Formation - Tenken for this cost.
Use these Fire Formation spells to support your Fire Fist monsters. Fire Formation - Tensu gives your deck some swarming capabilities by giving you an extra normal summon. Fire Formation - Gyokkou pins down an opponent's set backrow so that you can make your plays safely. Additionally, Fire Formation cards give your Beast-Warrior monsters small boosts which could stack up to be significant with multiple Fire Formation cards active on the field. Fire Fist monsters usually have effects that costs you a Fire Formation card on the field to activate making these cards also act as fuel.
Horn of the Phantom Beast boosts a monster you control by 800 attack which could help Brotherhood of the Fire Fist - Gorilla attack over a monster to search a Fire Formation spell. Also, when the monster equipped with Horn of the Phantom Beast destroys a monster by battle, you draw a card which could help you maintain card advantage with all the Fire Formation cards being used as costs.
Using the Fire Formation spell/trap cards, even the lower level monsters can get a pretty decent attack increase. The lower levels are mostly going to be used as ways to stall and protection until you can draw the higher levels. Starting with Raven is a good and safe option. Its effect will activate even if it's not destroyed by battle.
Both of the high level cards can be special summoned. Summoning Swallow will let you set a Fire Formation - Tenken from your deck. This can help boost all Beast Warrior type monsters by 300, easily making them high attack beatsticks. Special summon Coyote whenever you already have a Fire Formation spell/trap card that you control when you have no monsters on the field. This can also be used for tribute summoning into Swallow if you want to thin your deck faster.
Using Tensu, you can special summon Coyote and 2 other low level monsters. All of them will get boosted by 100 attack each from Tensu's effect, and you can activate Kaiba's skill "Beatdown" to increase all monsters by 300 as well. Tenken can be tricky to activate, but once you manage to do so, all of your Beast Warrior type monsters will get a significant attack increase.