I will try and add some clarity, forgive me if some of it is sucking eggs stuff.
Here is a link to team building that is a must read http://puzzleanddragonsforum.com/showthread.php?tid=2192
You have 5 team members, a leader and 4 subs.
You also have friends which you add and use as your 6th member and are also very important.
Lets start with your leader, when you start the game and do the tutorial you get a rare egg machine roll and you get a starter creature, after doing the 5 easiest dungeons you should have another 5 stones which gives you a second roll. Now these are pretty important as they guide you on your setup and starting teams.
Now all creatures have a team cost and the better the creature the higher they cost which can mean getting one while good you cannot afford to make a team with them yet.
Now most creatures have leader skills and secondary skills which you activate in game. The leader skills are very important. For example
Artemis has 2x Atk and 2x Hp for green attribute creatures. What that means is when you build a team of 5 green creatures all of them will do double damage and have double hit points. This makes you team 2x times stronger and 2x harder to kill. Even better get some artemis friends who are also x2 and all of a sudden you are x4 making you very powerful and with lots of hit points, however you will struggle with rcu(recovery or healing) so you are trying to kill them quickly.
Another option would be to use a Freja friend who has 2x atk and 2x rcu for green meaning lots of atk and plenty of hp and healing, its all about balance.
Anyways you really need leaders with multiplier leader skills of some sort, blocking damage against a specific colour while useful only works in those colour dungeons.
Here is a list of the best starter creatures, if you don’t want to restart and have very few decent leaders then it maybe worth spending some money on some stones and have 5 rolls on a godfest you should get something decent.
You really should read the above post to give you some help, its a quick and simpler read and will really help.
Now on to subs, at the start same colour teams are the easiest as matching 3 orbs of the same colour will make all your creatures attack and it is a lot harder to match 3 of each colour in 1 go so mono teams are easier.
Now to what subs to use, the main thing is there individual in game skill. For example in a green team a mystic green knight changes red orbs to green every 9 turns, so you need subs that enhance your team, for example on a healer team a Valkyrie changes hearts to yellow and a siren healer turns red orbs to heal orbs, so you use siren followed by valkyrie and you get half a board of yellow orbs to use say against the boss level.
Here is a simple guide to what subs you can farm for, remember the drop rate is very low so it may take a while to get them. Also the special dungeons appear every few weeks and are worthwhile doing regardless as some of the creatures they drop will become useful as you progress and find you now need them.
Now to the dungeons, you have 3 types of them, normal, special and technical that appear after doing Castle of Satan, the dungeons get harder as they go with a big step at CoS and Ocean of Heaven i think.
List of the normal dungeons http://www.puzzledragonx.com/en/normal-dungeons.asp
Now to special dungeons, these normally have decent creatures in which are normally possible to do at any level and have more chance of dropping the good stuff. You should do these dungeons as often as you can and you will get some decent drops, like Mystic knights, Echidna, Pierdrawn and so on, it may take some time and you may need to run then 7 or 8 times but it really is worth it.
Here is a list of the special dungeons so you can see what you can get and remember it may not be just the boss but others in the dungeon that are worth having.
http://www.puzzledragonx.com/en/special-dungeons.asp
Now the Tuesday, Wednesday and Friday dungeons have the materials you need to evolve you creatures and the harder levels are pretty hard until you get the right team and so you need a Zombie team or an Odin team. If you don’t have a decent healer, or an odin this is where your friends come in as they can supply them and those of us that still play have these creatures to help you.
Link to zombie team and how to do it is in the beginners guide to team building but is simple enough for anyone to do.
Additional things, use the pad forums to find out quick answers when stuck, also use it to find friends that have creatures that support your team and play, no point having friends you never use, get friend codes from the forums and send requests, people will accept you and it will make things much easier
Make sure those of us that still play are on your friends list most of us will have what you need. Hanacker, Hansey, Reemul, Maku and Jim defintely still play.
Maybe those still playing could put there codes up so Mixuk and Fire can use us.
To add Mixuk if you are playing the Uk version let me know and i will get you my uk code and friends codes soyou can add them all as there arent as many players yet.
Let me know if any of you need any more information and I will see what i can put up.