[subject] + 挺 + [adjective] + (的)
[subject] + 挺 + [feeling verb] + [object] + (的)
挺 goes before an adjective and means "quite" or "pretty". A 的 at the end of the sentence is common and makes it sound relaxed; it can be left off.
挺 is a conversation word. In writing, 很 or 比较 take its place.
挺 is roughly as strong as 很, and warmer. 很 is often just the slot filler before an adjective; 挺 adds a real, friendly "quite".
Verbs that take 很 – 喜欢, 想, 担心 – take 挺 too.
A negative adjective after 挺 is fine, and two of these are set phrases: 挺不错 "pretty good" and 挺不容易 "not easy at all".
Like 很, 挺 can't go in front of the adjective in a 比 comparison.