In which case
@dysonrichard801 has more or less listed most of the textbook factors that would lead to economic growth.
I would partially agree with infrastructure investment, because according to research the investment only really pays off if the demand is there first. Investing in infrastructure alone would not stimulate economic growth. It's like the idea of pushing on a string (a phrase commenting on monetarism); it doesn't really work unless the demand is there first.
What I would advocate instead of infrastructure investment is to either offer cheap alternative means of setting up businesses or providing assistance in trade (e.g. deregulation and lower fees to set up businesses or to provide alternatives such as permitting online offices and government grants for business startups).
If you're talking about international trades, you can talk about tarriffs and quota restrictions as well as offering currency based derivatives to hedge against exchange rate risks. In practice, you're also looking more into international regulations and standardising certain laws to help imrpove exports (the UK's is much left to be desired).
I have seen certain business support hubs set up to help the growth and development of startups e.g. Federation of Small Businesses in the UK. What can be done more is to provide some sort of business mentorship/apprenticeship program to help new businesspeople break into the industry. General education in business rarely does work, and it's usually more of the STEM subjects that tend to contribute more to economic growth via productivity and innovations.
Despite what they say about how innovation and technology is to be encouraged for economic growth, there is usually a lot of restrictions and hindrance to innovation and technology (the irony I know) e.g. survelliance, control, shelving discoveries, refusing to fund research and development, etc. Jobs in this part of the sector tend to be very poorly paid and somewhat "abusive" (for a lack of better term). If there is better support and regulations to protect innovators in the sector, you would often see a rise in growth.
I would also like to see there to be a change in laws in how the innovators are credited and how they should be allocated share of the rewards for their innovation. Current laws commonly states that any innovation an innovator creates belongs to the employer of the innovator, and the innovator gets nothing (no recognition, no renumeration, etc.).
The other textbook answers include: monetary policy, fiscal policy, control the costs of doing business (e.g. heating, oil prices, electricity, motor related costs, etc.)