When merging onto an interstate, you have to floor the accelerator (push it right to the bottom) to get the vehicle up to speed as quickly as possible. As you're coming out on the onramp and out onto the acceleration lane, pick your spot and aim for that spot. Other drivers will help you out as much as they can. However, know that the onus of responsibility is on the merging driver. Pick your spot, get the vehicle up to speed, and don't hesitate.