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Unfortunately, you can't make your hair grow any faster than what's normal for you. Average is 1/2" a month but everyone is different. And taking only 1/8" off your hair isn't even worth going for. What most girls do who are trying to grow their hair long is to simply go longer between trims. You can't grow your hair if you get an inch cut every couple of months. The recommendation is minimum 3-4 months between cuts, up to 6 months if you can manage it. Sometimes the hairstyle we have warrants a trim on a regular basis, and if this is the case with you, grow it out so there are fewer layers to deal with. Often times, a change in hairstyle that doesn't require as much maintenance or trims is all that's needed to grow some length. But your hair will still only grow at the rate that's normal for you. You simply have to be patient.
Also, not everyone can grow their hair long, no matter how little you get it cut. It depends on how long your particular hair grows before falling out and starting a new growth. Some people can only grow hair to their shoulders, and it's simply because every hair on their head will only grow for a couple of years before it falls out and is replaced by a new hair. Then that new hair will grow for about two years and fall out. People like that will never be able to grow hair to their waist because the rate of growth for their hair isn't long enough to accomplish this. You won't know if yours can until you actually let it go.
And if you have a person cutting your hair who really does not understand when you say, "Do NOT cut more than what I tell you", then find someone new. Hair stylists are a dime a dozen. Find one who will listen to you.