You can alter how far your objects should be distanced by pressing alt and using the slider in the top right corner. Most new mappers don't know that and I want to make sure that you know that. Also use a smaller grid size for better consistency (press g).
Use a preview point. That's the point where your song starts playing when selected in the map menu. You can to that in the timing tap at the top of the screen - it's the last option.
Use custom hitsounds - you know how to hitsound your map already, so why not even use your own ones? Even if you don't use at least some of the already impemented ones. Clap on 2/4 and 4/4 works most of the time to spice it up a little.
Find a picture with a better resolution. If you want to use your already existing one - drag the picture into the google searchbar - google will find it in a better resolution.
Also your Audio should have a higher kBit/s rate. 128-192 is okay.
If should have any questions regarding mapping PM me via forum or in-game ^^