We use the “Florida weave” method for trellising our tomato plants. This year we added some thick bamboo poles to our existing stash of untreated 1x1s, which don’t last too long stuck in the soil. You can find a more detailed description here, but all we do is stick supports in the ground every couple feet, wrap string or twine around the posts to secure, and then weave the twine around the plants. We add more lengths of string every 8-10 inches in a ladder-like fashion up the posts as the plants grow. We can also tuck vines up into the twine when they start to sag or get too close to the ground.
This method has worked really well for us, and has allowed us to get enough light down to the top of the beds so that our sweet potato plants can thrive.