It's always disappointing when a project doesn't come out as we hoped. I assume your scarf has a lace pattern and maybe the lace didn't open up enough during blocking to show the pattern. If this is the case, you can soak your scarf and block it again, and pull it open a little bit more when pinning it to dry. Hopefully, this will open up the pattern more. Another issue may be your choice of yarn. If your yarn has a lot of variegated colors, the pattern of your scarf may not show up. Likewise, if your yarn has a lot of texture, the pattern might get lost. If this is the case, there's nothing really you can do except knit your scarf again with a more straightforward yarn and let the pattern be the detail of your scarf.
Usually, a good block will straighten any twist your knitting might have. If blocking doesn't work, you can try ironing your scarf between two damp towels on low to medium heat. However, do not iron your piece if it has any cabling or other three-dimensional texture (like bobbles). I hope this information helps!