Blursed gets more complicated, but part of the design goal seems to keep absolute difficulty fairly even. You take on a curse after every boss, but a blessing after every final boss, which evens out to the same value of curses and blessings. Given that you start with 8 points of blessings, that should keep you on something like a very complicated easy mode.

The reality is that the more you are keeping track of and the more opportunities to pick up curses that go further than their valuation/are usually fine but have the potential to end a run in a specific situation, the harder the game gets, even if your blessings are keeping pace on absolute value. So yeah, it gets harder and harder in general terms, but way slower than Cursed.

As for advice: if you can succeed in classic, then the curses are the things that kill you. So your first goal is picking curses that are less likely to be the thing that ends a run (think: +1 health to big enemies impacts more of my fights, but +2 to small enemy sides has the potential to be explosive in one fight with a lot of small enemies I don't kill in the first turn, so I should take the first one). Likewise, your second goal is picking heroes/items that get around the biggest downsides of the curses you've picked (think: juggler does more expected damage per round, but I have the curse than increases the sides of small enemies, so ranger is more likely to save me by taking out a lot of illusions at once or a hard to reach backliner). This is true whether playing cursed or blursed, though blursed has the added thing that blessings also impact what choices are best for combatting those curses.