Avoid slopes as per usual. The first enemy you will want to eat will be the Yellow Shy Guy, and jump to collect the Flower. Swallow the next Dayzee. Next you'll want to jump and collect the two middle Red Coins, and do a descending neutral as you see demonstrated in the gif below. Grab the Green Shy Guy and with an upspit you can collect the Flower.
Just after the Incoming Chomp there will be four Red Coins with a small left right after falling you can collect them with a jump as seen above. Grab the Dayzee, and jump into the coins, spit the Dayzee into the cloud and collect the Stars with Yoshi. A back tongue shortly after should be used to collect the Green Shy Guy, save eating him until you pass through the Mid-Ring. A text box will appear, advance through it. You can see the back tongue demonstrated below in the gif.
For the pipe shots to collect the rest of the Red Coins in this room you want to run up against the pipe. Do a neutral and jump. Move across the pipe and do a reverse neutral to clear the rest of the foam as demonstrated in the gif below.
Avoid the Slopes as usual proceeding until the arrow sign as you see in the gif below. Jump when Yoshi is just past the arrow sign you will head bonk, and auto-flutter collecting the Red Coins, and the Flower.
After eating the enemy and running on the top of the slope to trigger a camera scroll jump eating the enemy above, and do a flutter to head bonk into the yellow section above. Hidden in this area is a Flower that you can collect with an upshot. The location of the upshot is demonstrated in a picture below.
Below you can see a new mechanic we haven't talked about yet in 1-1 and that will be used a lot in the rest of the run is Tonguing a wall. This will set Yoshi's movement to 0 and thus let you turn around immediately.
After landing begin an egg shot an angle like the one shown in the picture below will collect the last two Red Coins. Proceed down the pipe to the last screen.
Begin an egg shot as you fall through the screen transition, and do a shot into the cloud as you see in the video below. A left right as you land and a jump can collect the Flower. A descending shot shown in the video below can be used to break open the last cloud, jumping will get Yoshi into the explosion to collect all Stars. Eat the Dayzee, and collect the Pink Shy Guy for a Zewing Skip.