Athelney - they all start off the same, solve the clues and fill the grid, but then they move on to the 'endgame'. Often a few extra obstacles are added to make solving/grid filling that bit harder too.
Do you do the Azed crossword in Sunday's Observer? That's how I got interested in advanced cryptics (as they're known). Azed uses some quirky devices from time to time that help develop the mindset.
I'm sure you'll quickly get into the way of solving IQ if you try a few and then check their solutions - unfortunately, that involves waiting a couple of weeks for the solution to be printed. And they are quite time consuming, which can be off-putting. Good luck if you carry on.