This guide will let you know how you can get more than 8 characters in Day 1 to Day 55 Wishes on Adventure Rank 7. Go through the guide and follow the step-by-step instructions to get these characters.
You will need to complete the 3 story trials and come back here to reach Adventure Rank 7. 
Claim mail rewards to get x1760 Primogem, x10 Aquaint Fate, 10x Intertwined Fate to start doing wishes. 
Later on, you will be gifted 10 Acquaint Fates after reaching Adventure Rank 10. Spend your Aquaint Fates on the limited beginner’s wish for more rollouts. 
You will get one guaranteed character for every x10 roll out, the first character is Noelle, 2nd random and the banner goes away. 
Now let’s start rolling. 
Buy 4 more Aquaint Fates. This banner will more likely give you a character than the other banners left (About 85% guaranteed every x10). 
If you already got Venti like me, it’s better off switching to the last banner, in case you want to unlock more characters (Barbara and Xiangling can be obtained for free). For the last x10 rollout, convert all your Stardusts and Primogems left to be able to have 10 more of these. 
Was looking for Fischl so hard, that you have to stick with intertwined fates. 
If you pretty much got all the things you need, it is suggested to save them PrimoGems when you are once again also open an x10 offer. There will be able 5 more rolls but the chances are no good with the x10 guaranteed 4* 
You can always try on different username accounts and redo the first story missions if you have another character in mind, which takes like 40 to 50 mins.