10km Run Goal

Hi all! I'm back on the fitness bandwagon after a heavy few months of holidays/family visits - essentially too many wine and carbs! And one of the goals I wanted to set myself this year was running a 10km in April. Pre December I was running 5km once or twice a week. But I never seemed to be able to push past that point. I mainly run on a treadmill at this point, because I live in the North of England where we only have like 5 hours of daylight this time of year! Any tips for getting to that 10km goal? Or anyone else with similar goals who want to share the journey with me? Thanks all!