Press the magic button? It sounds like you think there is some secret formula for success. There isn't. There isn't one way to win. There isn't a "win it all" formation, role, or Team Instruction. There isn't "win everything" signing either. You just need to be careful and logical with how you set up.
Start by analyzing your squad. The Team Analysis screens do most of the work here. Where are your strengths? Where are your weaknesses? How do you compare to the rest of the league? A league like the Championship has a fairly broad sample of player quality, so you might look at a given player and think they aren't that good.... but they might actually be pretty decent for the level.
Now that you have an idea of where you are good and where you aren't, figure out how you want to play. Not formation, but tactical approach. Don't confuse the formation - literally how the players line up on the pitch - with the actually tactical approach. How do you want to defend? How to you want to attack? This is where some basic logic comes in - consider what you just figured out with your strengths and weaknesses. Those don't HAVE TO dictate how you approach things, but it generally makes things easier. If you have a squad full of hard-working, aggressive, tough players who severely lack in technical quality, deciding to play tiki-taka passing football isn't outright impossible.... but its a LOT harder to make work. Make things easier on yourself by picking a style that fits. Look at strengths and weaknesses - again, its just logic. If you have no wingers, you will be narrow and that leaves space. If you have 3 strikes up top, you will lack bodies elsewhere. If you play a high line, you can get hit over the top on counters. This doesn't take tactical training to recognize basic problems, but there are a lot of folks who post on forums (here and elsewhere) wondering why they leak goals when they have a back 4 with wide defenders who mostly attack and no DMs.... 3 seconds of thought should be enough to tell you that you are defending with essentially 2 players, so what kind of "effective defending" are you expecting?
Once you have an idea of how you want to play, then pick a formation. Again, be logical. If you want to be more defensive, have more players back. If you want to be more attacking, it can help to have more players forward. Look for balance. Pick roles and duties that suit what you want to do, not that simply fit what the player "does best" based on the rating. Be logical and look for balance. Don't add Team Instructions for the sake of team instructions. Pick your formation, shape, mentality, and roles / duties, then see how it plays. Add TI if needed from there. Not before you know how it plays without the TIs.
You can find success playing almost any manner, if you set up properly and tweak. You can be super-defensive or pretty attacking. Any approach has positives and negatives. You can't eliminate all weaknesses. The Championship is pretty diverse in quality so you will face Prem-caliber sides and sides barely fit for League One. Generally, until I have a squad that is a clear step above the rest of the league, I tend to adjust slightly when I play away from home or against tougher opposition. Not massively changes, but small adjustments. An absolute key, I find, is watching the matches. Look for issues. Tweak to try to solve those.
This probably isn't what you are looking for. But no one is going to be able to simply give you a list of "tactical things" you need to do to succeed. Even if you posted the full tactic you are currently using, we can at best suggest tweaks based on the issues you've observed. But again, no "win now" when it comes to tactics.