The best way to be at the proper gentle effort when you’re trying to run more is to start more slowly than you think is necessary. Instead of forcing things so that you’re at the pace you “should” be by the time you’ve gone around the block, start at a trot. As your heart rate increases gradually and your muscles start to warm up from a gently increasing blood flow, you’ll naturally feel like running faster, without even having to think, “OK, now I feel ready to run faster.” Within 10 or 15 minutes, you’ll find that you’re running much faster with almost no increase in your perceived effort.