I never made spaghetti squash because the thought of making it intimated me. One day Marcy Tillman from Laguna Beach showed a bunch of us the ropes. She said to stab it all the way through with a knife and slam it on a step. (outside of course). If you have someone with muscles around, they can cut it longwise starting in the middle.
Next clean out the inside with an ice cream scoop. You then roast them at 425 for 40 to 55 minutes. (Depending on size.) You want to stop cooking the squash when you can take a fork and comb through the squash. It's strands should be soft but not mushy.
My husband actually likes to scrap all the cooked insides out when they are still firm and saute the squash in some butter and chicken broth. Not only does this make the squash yummy. It gives you control over how soft it is.
You can serve it lots of ways. For instance: Greek style with olives, tomatoes, feta, balsamic dressing, etc., or spaghetti sauce. The classic way to serve it is with butter, parmesan and garlic. I prefer the butter route. (There's a reason why I'm a bit rounded.)