My practice always, was to take off with a stomp on the slow pedal, at the same moment I open the gas valve full. As soon as I hit say 10 MPH I knock off the gas and release the slow pedal. From there on I am in high gear, using the valve to regulate speed.
If mixing with traffic is your issue, claim your SENIORITY, be sure to have a good working horn, and USE it. Use it for attention, use it like toy. Wake them up to your presence. They often need a double take to penetrate their airconditioned,, music and media,, device laden,, experience!
If pulling in high at a low. slow speed ( Level Ground as a Roundabout ) is difficult, get with an experienced tuner to find the answer. The power should be there.