Edge your garden beds. Nothing makes your garden look neater than a nice, crisp division between lawn and bed. Although there are mechanical and gas-powered edgers that do the job, the easiest and cheapest way is to put down a strip of cardboard about a foot wide around the bed and cover it with mulch or wood chips. This gives you a visible transition from one plane to the next and makes it easier to mow to the edge of the lawn without nicking your blades on brick or stone borders.
Get used to the ants! Every time I move a pile of pots, I find another anthill. Yesterday, I moved a large pile of pots, and I believe the earth moved. Not as fast as I moved, though, believe me. They don't generally harm plants, so unless they decide to come into the house, leave them in peace in the garden.
Cage your tomatoes before they get too big. Stakes and wires get them up off the ground, but my favorite supports are cages. A full-grown plant can weigh more than 30 pounds, so you'd better make a show of strength. Most cages on the market are ridiculously wimpy and about as strong as coat hangers, so buy the biggest, heaviest four-legged ones you can find. They're strong enough that I also use them to cage dwarf fruit trees. The heavy ones last forever but are expensive, so each season I buy as many as I can afford without dipping into my IRA. Then take the little label that came with the plant and duct-tape it to the top end of the cage, because once the plant gets going, you'll never see its feet again.