You've implemented your program and things are looking good, but there is one weed so dastardly, damaging, and diabolical that practically nothing can touch it... creeping charlie, also know as gill-over-the-ground, creeping jenny, ground ivy, and several profanities not to be mentioned here. This is simply the toughest, most vigorous, and most invasive weed on the block. This weed was brought to North America by European settlers who thought it would make a good ground cover (silly Europeans). It has bright green round leaves with scalloped edges, and produces small purple flowers in the spring, when mowed or crushed it produces a strong smelling mint-like aroma that can be overpowering, and it will grow anywhere. The main problem with controlling creeping charlie is the way it spreads, it puts out long runners like a spider web, each runner puts out new roots every few inches, so practically every leaf becomes another self sustaining plant. This stuff slowly starts creeping in from adjoining lawns, and once it takes hold, watch out, it will block out the light and slowly kill your grass, and any other plants it can cover. Pulling it or raking it, are an exercise in total futility, as you can never get all the root and stem system out. The only method of eradication I have found effective is a product called Trimec +++ (not to be confused with regular Trimec). This stuff is available at nurseries like Campbells and Earl May, you mix with water and apply it with a garden sprayer. It takes two to three applications, one week apart to completely kill the weeds, and best of all it will not harm your grass. The best time to apply this, or any liquid herbicide is in the fall when temps are cooler, plants are actively growing again and trying to absorb as many nutrients as possible, they really suck up the product thoroughly and allow it to work effectively. Keep an eye out for future invasions and spot treat as needed. Here is the link to the Trimec +++ Site, and some pictures of the enemy up close, and an infested lawn. Happy Growing.