I still don´t see enough information to try to help, but I will make 2 recommendations.
1. Tell us what model, where it´s balanced, what the control throws measure, and how you launch it. A description of the power system wouldn´t hurt, either, to include motor description, gearbox description and ratio, prop size and pitch, and battery cell count and mAh.
2. I will make a wild guess that you are handlaunching, and offer some advice. To hand launch, at full throttle, throw the plane gently at the horizon. Not above, but possibly below the horizon. Then the plane is descending when it leaves your hand, and gravity will help it gather speed. Wait until the last instant to pull the elevator, so the plane has gathered all the flying speed possible. Then make the SMALLEST Possible elevator input, to avoid that overcontrol which makes them snaproll into the ground. Usually, just touching the up elevator control is sufficient to get the plane flying level, so you can gather more speed. Later, you can turn, and gain altitude.

If this helps, let us know. If not, let us know that, too!
Good luck,
Dave Olson