I could probably spend hours answering both questions... These aren't easy topics, and I'm pretty busy at the moment so you'll have to make due with a short response!

Light/glow effect:
Your model will need 2 materials (one for your base texture, and the other for the parts that will glow). In blender, assign each material to the corresponding vertices and unwrap like you normally would. If you did this correctly, in the in-game importer you will see options for two materials. Load your base texture for the first material (and set the vmt parameters like you would normally), and then for your second texture load in a secondary texture that is completely yellow in color (or whatever color you want) with a fully white alpha channel. Make sure to check the box in the vmt parameters that corresponds to self-illuminate, and this will make that specific part of your model glow.

Holes through shapes can be done in many ways: extrusions through cylinders, using modifiers, etc. If you are looking to generically put a hole through geometry, you can use the boolean modifier for this (warning: this can drastically increase polygon counts if you aren't careful with how you do it). Create a cylinder > position it through your model where you want the hole to be > add a boolean modifier to your model > in the boolean modifier's object subheading, choose the cylinder you created > make sure the operation is set to "difference" > hit apply modifier.

As for indenting objects, you'll just extrude faces for that. Create edges loops (or use the cut tool), then select the faces you want to indent and extrude them inwards.

Thank you for the helpful reply HellJumper. Okay, last question... How do i mould a object to a face. Say im making a "mask" for the sniper. How do i mould it around his nose, cheeks ect. Because so far i make it and its a completely straight mask and it just sits there, I cant form it to the face without making the model go very weird. I try rotating ect and all it does is stretch the shape making it look all weird. Is there a way around this such as building it onto the snipers face or something like that? Because i cant seem to do it.

Thanks for taking the time to answer my questions.

Do it manually.

Create a bunch of edge loops and start moving rows of faces inward and outward.