Hello and welcome to the forum. Congratulations on starting up your own business, it's hard but very rewarding.
Get yourself listed on all the free business listing sites. Places like Gumtree and Shpock are also worth using I find. Have a decent social media presence with Twitter, Facebook, Instagram etc. accounts, which you post regular content to. Have a professional and accurate website that's informative and ensures people have a call to action (click for a quote/call for a quote etc.) And if you can have regular content on it, perhaps a blog about tips on dealing with pests, or interesting facts about bugs etc. Become an expert in your field. Google likes be content and regular updates on websites.
For your type of business leaflet drops may be worthwhile too.
Good luck with it all and this forum is here to help so please ask anything you need to and there's sure to be someone on here with advice or a recommendation.