Hello everyone!
After looking at some old and recent decks I realized that people really don't know how to make a good Digimon deck.
So I took it upon my self to make some tips for new players.
Here are some tips:
Have a good array of Rookie level and Champion level Digimon.
Have at least 3 to 5 Rookie Digimon and about 5 to 7 Champion level Digimon since these are the most common levels played in this game.
Also when choosing the Rookies, make sure they can Digivolve into multiple Champions. It makes it easier when dealing with a tough opponent.
Keep the number of Ultimate and Mega level Digmon low.
I know this sounds odd, but believe me. Getting up to Ultimate is already an achievement and it's very rare for someone to make it all the way to Mega.
Keep the number of Ultimates around 3 and have no more than 1 or 2 Mega Digimon.
Have a good assortment of Battle Types.
Red, Green and Yellow are the only 3 battle types in Digimon and having a good assortment can make a difference. Never make a Mono Red or Green Battle type because you will be sure to run into some trouble.
Always have decent amount of Digivice or other Digivolve cards.
Digivolve cards are used for Champions to Digivolve to Ultimates and Ultimates into Megas. It's always important to have at least 3 in a deck just in case you get the chance to advance to Ultimate or Mega.
Power Options/Power Blasts are you best friends
Always have Power option cards which power up your strength or which Void your opponents cards. "Option eater" and "Power Freeze" are good examples of those.
Well that's about it.
Also to facilitate your attempts to make great Digimon decks, check out this site!
http://thedigi-zone.com/Card%20Scans.php
Have fun!