Since I don't think SI will ever introduce difficulty levels or something like that, there's only much you can do to make the game more difficult:
1) Play with a skin that hide your players attributes. You'll see the difficult of this when the transfer market is open: every player you buy has a bigger question mark and you can really end up having a bad season following a bad transfer window. Specially in lower leagues where you don't have that many scouts and most of the players you'll bring won't be fully scouted (if you limit trials, another difficulty layer).
2) Use the in-game editor to help other teams in your league. I know this isn't ideal, but a way to "fix" the bad AI squad building* is to just do it yourself. I always make the big teams in the league I'm playing stronger by getting them players with higher CA in positions they lack. Also, I tend to send youth good players from them on loan to other clubs in the league to strenght other squads and also give them playing time. If you want to go one step further, you can increase morale and tactical familiarity for those teams.
3) Don't play in England. Start a lower league save in a different country, the smaller and unknown that country is, the better. You won't have access to a big player pool to strenght your squad originally, so you'll just struggle more.
Eventually, the game will become easier and you'll dominate your league. But that's just because you can overwhelm the AI in almost every instance. It's just the way it is. I do believe that SI should aim to a difficult game, where squad building is a challenge, but I do know that people gets frustrated when their lose, so I think I'm in the minority on this side.
* When you think on squads independently, then yes, AI squad building is "poor". But when you take into factor that the AI has to build thousands of squads every transfer market, where players are moving constantly from one side to another, and provide a balanced squad for each one of them, I think it deserves some respect from SI devs. It's not easy to do that and there're improvements edition after edition.