@PreHax Thanks for the guide!
I think under the section for the lake that requires a max happiness Starly, we can add a tip (got max happiness from default within 5 minutes, got the idea from watching one of Carlho's quick lvling videos).
*Recommended for the Starly to be very low lvl to max happiness through this method asap*
If you have a pokemon with false swipe (and ideally holding the item "Black Sludge," but not necessary), you can send that pokemon into battle first, keep spamming false swipe until your pokemon faints, and switch into Starly (ideally holding "Soothe Bell"). Starly learns quick attack at lvl 5 so you will have the priority and be able to faint the opposing pokemon since false swipe should have lowered it to 1 HP.
You gain a lot of happiness upon leveling, and your Starly would level a lot through this method. I recommended surfing south of Sandgem and doing this method on wild, evolved pokemon (they give more exp). Or, you can just surf in the Verity Lake.