I prefer to have the bottle standing right-way-up as I think it looks nicer and it keeps debris out of the bottle thus keeping the holes from blocking.
The materials:
* 2 litre plastic soft-drink bottle or water bottle * Sharp small screwdriver, pointed hole-maker or drill
Using your pocket knife, make 2 small slits in the bottom of your bottle. Make two more small slits half way up your bottle. Then fill your dripper bottle with water to test it. Does it drip slowly? Or empty too quickly?
Dig a hole next to your tomato plant. Place the bottle right-way-up in the hole. Fill the bottle with water from the hose. Add liquid fertilizer from time to time.
This will slowly deep-water your tomato plants and most other vegetable plants.
Only two very small holes are needed at the lowest place on the bottle.
I prefer to leave the lids off. This means I can fill them in a shorter time each day without removing the lids. If you replace the lid on the bottle after filling with water it will release the water more slowly. You might like to experiment with this.
Place bamboo stakes next to each bottle. As the plants overgrow the bottle, you will still find it by seeing the stake.
Here I am making another hole slightly higher up the bottle. If I screw the lid on, this hole acts as a breather. Water will not come out. Air will go in. Try this.
However, if I remove the lid, water will come out this hole as well as the holes in the base.

You can make larger holes, and partly fill the bottle with coarse-sand or soil to slow the flow.
Fast fill. Slow release.