A few achievements are granted just for starting the game and doing basic things. The rest require you to get high scores in the game. You only get points for picking up "lettuce" and money. Lettuce also gives you "fuel", which you need to keep going.

The last achievement is for going 100 distance. I found it easiest to avoid the speed boosts. Don't forget to pick up fuel.

Tips:

• The big clumps of lettuce give more points, so prioritize those over smaller ones.
  
• Money gives points equal to 101 x its number - with this addition the score achievements are trivial.
  
• The snail's hitbox is actually pretty accurate, so you can thread between enemies/obstacles.
  
• You can pick up big clumps of lettuce even when enemies are on top of them, except for spiders. Just don't get too close.
  
• You can move to the very edge of the track and have enough room to clear bees, centipedes, and ladybugs.
  
• If you hit two speed boosts close together, you can kill enemies by running into them for a short time.
  
• Use the Upgrades menu to get some useful abilities if you have enough snail dollars.

Enemies:

• Bees - fly straight down the track at a quick speed
  
• Centipedes - move straight down the track at a slow speed
  
• Ladybugs - move straight down the track
  
• Spiders - move straight down the track at a medium speed and are wider than the other enemies

Obstacles:

• Rocks - just move around them
  
• Salt - instant death, always avoid