If you're new to OpenGL, it's almost a rite of passage to write your own shader class and model loader. To help you out, I ripped these directly from my own renderer (Mirage), so you'll see a bunch of references to it in this sample code. I wrote this when I was still in college, so there are definitely some warts in my code.
If you're following along with a tutorial, you'll want to read through this one first. The shader class covers how to load a GLSL shader source file and turn it into a usable OpenGL shader object. I wrote it in a fashion that allows you to "chain" attach calls, like in JavaScript.
Shader shader;
shader.attach("main.vert")
.attach("main.frag")
... // and so on ...There is some basic error handling to help you out if you get stuck.
Model loading is a bit harder. Most standard models are actually comprised of multiple, "sub-models" (or sub-meshes). For example, a character model in a video game might have a "torso" section, a "left arm" and a "right arm" section, and so on, all inside the same model file. Here I provide a sample mesh class that will handle multi-meshes; the screenshot on the main page is one of them!
Most OpenGL tutorials will guide you through writing a standard "Mesh" class, which involves writing a standard tree containing a set of nodes. This entails a containing "tree" class, and a "node" class containing data. As an alternative, I wrote an intrusive tree implementation, which stores the tree relation directly inside the nodes. This Quora post might be helpful in understanding what an intrusive data structure is, and why they are used.