Are you suppose to eat before or after you work out? 
How do you know when you pushed yourself far enough?

Eat before or after working out makes little difference, if you are eating healthy. It's a matter of preference, I usually eat beforehand, although I do work out at night, so that might have something to do with it.

You'll know...well, when you know. When you've reached your limit and kept going, when you quite literally can't do anything else. The human body can reach amazing heights, breaking limits after limits. Just keep going, you might think you can't anymore, but if you try, you can work out for so much more than you'd think.

Although, if you feel like you've hurt a muscle, bone, area of the skin, etc...
You should stop doing whatever you are doing.

Also, just a tip, don't like...stretch before a work out, Do it after. Stretching loosens joints, which can lead to accidents during the work out. Plus, it's meant to increase your flexibility, not to "warm-up"

I like to have a light meal an hour or two before I work out, and then a big meal after I finish working out.

You'll know you pushed yourself far enough when you literally cannot move another muscle. Of course, this is also a good way to get hurt if you do not know your limits.

If you do not know your limits, you have to figure that out. Of course, if you knew, I don't think you'd be asking.

You should give 100%, but be smart about it. After all, the brain is part of your body that needs training, just like an arm or a leg.

I can't eat unless it's 4-5 hours before working out, unless it's apples, or possibly granola bars.

I also push myself fairly hard.

In terms of knowing your limits, gauge your soreness the next day. The most important thing (in my opinion) is sustainability and repetition. If you go hard one day, and then can't work out for a few days after that, then you're pushing too hard.

I recently started running again. I ran 3 miles on Sunday, and 4.5 on Monday. On both days I felt like I could go much further, but I held back because I knew I'd be incredibly sore the next day (and I was), and I want to keep my running sustainable. So I'd suggest building into it, finding your limits (like legacyme3 suggested), and keeping it sustainable.

I prefer eating after working out, whether it's lifting weights, tennis, or anything. I don't like having all that stuff sloshing in my stomach and feeling all full and tired while I'm working out. It's also good to eat after working out because you could kind of see it as a reward for doing well when you are done.  Also, when you're energy is all low when you're finished working out it's good to replenish it. That's my experience

I dont do major workouts, but I walk a lot. Even when I'm only doing my own stuff and don't actually want to excerise, I still walk over 2 miles in a day, and before I head out I have something small like a bagel.

Lily, what are you doing for work out and what are your goals. That will make a difference on when you eat in relation to your work out.

Everyone is different.  It doesn't matter if you eat before or after as long as you're eating at some point.  If you know strenuous exercise is coming up, most folks eat about 2 hours before and nothing heavy.  Drink water and stay hydrated.  That's the important part.  The food thing doesn't come in unless you're really doing some heavy work, like running seven miles or more or doing 90 minutes of heavy cardio or weight lifting.

Most work outs won't require refueling between or immediately after exercise.  Just have some water.  You'll be fine and that'll do most of the work for you.  If you experiment, you'll figure out what you like the most.

Everyone Thanks I kinda figured the whole go until you drop thing but I couldn't remember if that was dangerous or not. I just started working out and the first day I after and the second day I did before. I like how I feel when I eat before.I feel like I have more energy and the work out was a little easier. I also didn't cramp as much during. Right now I am really sore. To be honest I know nothing about working out. Right now I just start of with 30 min power walking on the treadmill than I been switching back and forth from legs to arms  each day on various weight machines.

Light Knight : To be honest my only goal is to loose weight and eat better. I haven't touched the scale and  not counting calories yet. I am so far gone that at this point even the smallest effort will make a big difference. The only thing I have committed to is going to the gym Monday through Friday for an hour, drinking a gallon of lemon water through out the day, and no ordering food just bringing my lunch to work. Its not much but its more than what I have been doing. I am afraid to set a goal for myself because I know I will just end up disappointing myself and will end up in the same spot I am now if not worse. 

lilythetigerkity : That's an awesome goal and way of doing it.

While you need some energy to exercise, if you exercise with little fat in your digestive system, you will loose more fat in your body. While I certainly don't recommend it,  some fitness nuts will do cardio first thing in the morning before eating ANYthing, to burn more fat. You could do something similar, but just eat a little something before. Something with a little bit of good sugar or carbs (like a banana) and some protein (greek yogurt, an egg), but as close to zero fat as possible. You could do the same thing after work/school, instead of having a supper or completely starving yourself and then working out, have a small something with a little carbs and some protein and go do your workout.

Then after your workout you can have to more full dinner or breakfast.