Start out by trying to play [Hiro Amanokawa] while breeding [Gammamon].
[RB1-005 Gammamon] is great for getting these cards ready as it allows you to add 1 [Hiro Amanokawa] and 1 card with [Gammamon] when you play it!
Just combine the above strategies with [RB1-008 BetelGammamon]'s When Digivolving effect, and you'll soon be ready to take on your opponent!
In the middle of the game, you can use the respective color traits of [RB1-015 Fumamon], [RB1-023 Ghilliedhumon], and [RB1-030 Regulusmon] to respond to various circumstances.
In addition, [RB1-009 Canoweissmon] has an effect that allows it to immediately digivolve from [Gammamon].
You'll be able to recover no matter how many times your cards are defeated!
Towards the end of the game, use level 6 [RB1-010 Siriusmon] and [RB1-031 Arcturusmon] to control your opponent's field, then use repeated deletions and card plays with level 7 [RB1-036 Proximamon] to dominate your opponent and come out victorious!

When starting out, use [RB1-011 Jellymon] to search for a digivolution line and Tamers! Use [RB1-013 TeslaJellymon]'s effects to play [RB1-033 Kiyoshiro Higashimitarai] or [P-064 Kiyoshiro Higashimitarai] and get ready to attack! Make consecutive attacks with [BT9-025 TeslaJellymon] or [BT10-023 Thetismon] and use [RB1-014 Thetismon]'s When Digivolving effect to trash cards from your hand. Then you can return cards with [Jellymon] from your trash to the bottom of your deck, allowing you to use [RB1-014 Thetismon]'s inherited effect and [RB1-016 Amphimon]'s deletion-preventing effect to increase your offensive abilities!