How to make my tomato plant healthier?

Sevin dust

Hornworms or slugs possibly. Neem oil is what I would use.

https://www.gardeners.com/how-to/tomato-pests/5086.html

http://www.tomatodirt.com/holes-in-several-tomato-leaves.html

https://youshouldgrow.com/tomato-leaf-problems/

Occasionally I get hornworms. I just pluck them off by hand and toss in the green waste bin.

Buy Nematodes for soil,Live Lady bugs,Pratying Mantis Egg cases,Green Lacewings,& Pirate bugs,Parasitic Wasps all these benewficial bugs I use in my garden Never used any pesticides,in my garden areas. mosquito dunks or bits in soil or areas to kill mosquitos and fungus gnats. I buy most items from Arbico Organics.com High Sierra lady bugs or Praying Mantis egg cases on ebay. Earthworms or Red Wrigglers for soil from Uncle Jims Worm farm. only pesticide I 've used is Amdro ant bait for gravel sidewalk driveway in front of house and only if constant flooding of colony with water will not get them to leave area I need to walk or stand. Ants are needed/beneficial to pollination of plants and break down of organic waste on/in ground

You could try spraying with a mix of 1 part liquid hand soap and 40 parts water. Let sit for about 10 minutes and then spray off again. Do not do this in the hot sun, better in the shade.

This link might be helpful.

How to identify tomato pests and control them

http://www.tomatodirt.com/tomato-pests.html

Additionally, The key steps every gardener should take to sidestep or minimize common tomato issues. Those steps are:

1 Mulch

2 Support

3 Prune

4 Water

5 Feed

6 Monitor

7 Act

So, let’s take a closer look at each step.

https://joegardener.com/podcast/tomato-care-checklist-craig-lehoullier/