I'm not a native speaker and I am not the best to teach you,but let me try to give you some help.

A checkout

1.1 comparative and degrees
Sweet - sweeter- the sweetest
Far - further- the furthest
Good - better- the best
Expensive - more expensive - the most expensive
Rich- richer - the richest
Ugly - uglier - the ugliest
Terrible - more terrible - the most terrible
Young - younger - the youngest
Hard - harder - the hardest
Steep - steeper - the steepest
Small - smaller -the smallest
Narrow - narrower - the narrowest
Shallow - shallower - the shallowest
Powerful - more powerful - the most powerful
Bad - worse - the worst
Strict- stricter - the strictest
Fat - fatter - the fattest
Healthy - healthier - the healthiest
Wide - wider - the widest
Cheap - cheaper - the cheapest
Elastic - more elastic - the most elastic
Clean - cleaner - the cleanest
Solid - more solid - the most solid

Comparatives and Superlatives are fine I think.

1.2 UsageS
1. That bar of chocolate is more solid than this one.
2. My car is cleaner (Than what?)My car is cleaner than yours.
3. The Amazon river is the widest river in the world.
4. Vegetables is(are?) the healthiest food.
5. My parents used to be stricter.
6. His girlfriend is younger than mine
7. Mount Everest is the highest mount in the world.