sorry for my late response ... pls check the attached image ... It's a good try ... but I felt there is few points which u may be useful .... always check the silhouette in ur 3D software by keeping the model in black with the brighter background .... this will help u to understand the volume and mass from different angles .... also in the beginning of the modeling try to see the ref as blocky structures and after finalizing that go for more details with making it soft and organinc ... my words will be more clear if u will watch my rough image .....