I've recently started trying to get into photography as a complete novice. Just started a class at my local community college using an old DSLR (Nikon D70) I borrowed from a family member. My first attempt spending a couple hours taking photos went well, got some random blurry shots but plenty that turned out fine. Went out yesterday and despite shots appearing in focus when I took them, almost every single one was blurry to a lesser or greater extent (pic related).

What are some possible causes for my shots turning out like this? Something I'm doing wrong, something wrong with my equipment (the camera and lens are pretty beat up)?