Hi Seihime,
Fellow G2P (Gratis-2-Play) gamer here - haven't spent a single cent on the game, been playing around a year(?) or so, level 70 now. I just recently built up a "starter" AW killing team with HSR Joker (Sickle) + SR Omoikane (lucky Ultimate Summon), so you can add me if you have room - I still have open slots: 2cr5l
With the introductions out of the way, let me quickly summarize what I've been doing to slowly build up my team ... with lots of advice gleaned from this site, from the TCGapp forums and from their Facebook fan page. WARNING - LONG POST!
To make the best of playing this game, you must first understand these concepts:
1) Build a kingdom that never really lets you run out of resources, so upgrade all your resource providers! Also upgrade your Castle to get more of them. The starting will be slow largely due to this part. It was EXCRUCIATING for me to get to where I am today - Castle Lv9 (level 10 requires 2000(!) diamonds)... I've not even maxed out all my resource providers!
You can build other impt structures like Arena, Barracks, Temple, Alliance house when you have resources to spare. Hold off on extraneous structures like Fortress, Saloon, Parlimentary House, Goddess Statue/Fountain for later.
2) Accumulate the most important items for early players: Slimes and Medals. focus on leveling Slimes only up to lv27 by feeding them N/HN cards. Then collect Wizards from WoG area 2 and Summoners from WoG area 4 to amal them into Sage, then exchange Sage for 100 medals each. Using these medals, purchase Arcana Blessings and Successions. Medals are also needed to level up your cards' skills - though you should be picky about which cards you plan to level up skills... stick with those that are AoE (Area of Effect, multiple targets) like team healing, all-enemy attack, or enemy ATK debuffer.
Feeding R/HR cards with a Lv27 slime + Arcana Blessing (x2 exp) will guarantee you the fastest way to level up to MAX. Alternatively I think you can also use TWO Lv27 slimes to MAX a card. Early on if you are able to acquire a number of slimes, you might go with the TWO-Slime method to save on Arcana.
3) Ok, now you know what it will take to get resources, medals and use Slimes + Arcana, we can get down to Team builds. First things first. build 1 (or more) high-level HR Android! She will be act as your team leader for many, many battles (even stronger than some low-tier SRs). Android is the result of amal between Enchanter & Mechanic. Enchanter can be farmed in WoG area 4 I believe, and Mechanic is available in WoG area 6(?).
To ensure the strongest possible Android, you MUST MAX level your Enchanters and Mechanics. Once you have a MAX level Enchanter and Mechanic, amal them into a Android. Then MAX level your Android. Repeat this procedure again to get a second MAX level Android. Once you have TWO max level Androids, you can evolve them WITH a Arcana Succession (5% stats transfer) to get a strong HR Android with good soldier count!
If you have enough resources and time you can build a 2nd HR Android if you like.
So you have your lead card, 1. HR Android. Next, I highly suggest you level up these cards (as always, try to MAX level cards just before HR evo grade to improve stats and soldier count.. use Arcana Succession sparingly, just on cards you wish to keep in the long run) and add into your regular team:
2. Astraea (AoE - Area of Effect light damage dealer, MAX level her)
3. Dike (AoE light damage dealer, MAX level)
2. Ninjya Dealer (AoE fire damage dealer, MAX level)
4. HR Aqua Knight (Singular damage dealer, the stats found in wikia are not MAX level)
Alternatively, you can try swapping out the R cards above for one of these cards:
HR Shaman or HR Ratatoskr (team ATK buffer, increases chance of AW field activation tho :(
Diva (enemy DEF debuffer)
Other cards you can keep around if you have space, else just exchange them for medals (some cards I keep when I like the art and wish to evolve them ;) . I highly suggest you look out for AoE healers to place into your team... these are great in reducing the cost of losing cards in battle (I personally run both Chocolate AND Kudashidahime in my AW team - they are crucial in keeping my battling team alive!): http://valkyriecrusade.wikia.com/wiki/Category:Heal_%28Team%29
4) Participate in AW battles, even if it just to take a swing at them, go for it! Then send your AW to your high-level buddies for the kill! Don't spend more than 2 BP (battle points) on any AW. This way you will ensure you have enough to keep luring out AWs! One thing to note - don't be tempted to immediately open the treasure chests after each battle...
Something I wished I learned earlier is that when getting new cards thru diamond summon or in Archwitch treasure chests, it pays to first completely load up your cards box until it's full (75 cards), that will force the new cards into your presents box. This way you don't be forced to hold R cards (that you wish to keep, but don't need right away) in your precious box space. ;)
5) Another interesting tip: a quick way to level up slimes that I've learned is to form one team with a leader card with EXP bonus (like Star Reader, Detective or Devil), the fill the rest of the slots with Slimes. Level up your leader to MAX so that she can at least deal some damage and take some in return. Then keep your eyes peeled for AW with lesser HP. You can use your AW battling team to knock it down until less than 2000 HP, then opt to "Flee" the battle. Then return with your Slimes team to kill the AW. That will give the Slimes LOADS of EXP! I personally have a 4-star MAX lv Star Reader with Level 10 exp skill (+60%, lots of medals, but its worth it :) so it works great to level up my slimes quickly!
6) Keep your eyes peeled for new Quests! Some of them are easy ways to get EXP and diamonds! btw, I heard that the Castle in your kingdom will now offer free vitality refills randomly between 2200-2300 hr JST, look out for the shoes icon floating above it! I've seen it 3 times so far. :)
7) Also, always remember that you get EXP when retrieving resources, so when you are close to getting to the next level, go and battle in WoG or hunt for AWs first, to use some of your vitality or BPs before you move up to the next level... I don't know how many times I wasted the free level-up refill without realizing because I was in a rush to refill my resources. Grrr! :p
8) OH OH OH... almost forgot this last tip - SAVE your premium summon tickets and free diamonds! Wait when there are special promotions, like when they doubled maiden tickets (missed this promo!) for premium summons, lower the price of summons (like currently, premium summons starting @ 50 diamonds, I'd go for just the daily 50 diamond summon), or when they lower the cost of buildings (I also missed the earlier deals for 50% off Magic school and Yiggdrasil! :(
Alright, that's all I can think of... good luck! :)
Mr.Popo