Form and rules
How it works
Much, far, a lot and considerably strengthen comparatives: far more efficient.
A bit, a little, slightly and marginally soften comparatives: slightly cheaper.
By far commonly strengthens superlatives: by far the best; easily can have a similar function in some contexts.
More and more / increasingly describes gradual change; the more..., the more... links correlated changes.
Use nowhere near/not nearly as...as for a large difference and almost/nearly as...as for a small difference.