My achocha hasn't seemed to start setting fruit yet, and was wondering what tricks I should start trying in order to get fruit from the plant.
There are two primary methods to force flowering; shorten the day length of light to 12/12 average...and do not over do the nitrogen.
Your fertilizer is important. N-P-K a balanced basic fertilizer is critical. If these numbers are out of balance you aren't in 'control'. N-P-K with N as the largest number meaning the percentage of that chemical in that bag is higher than Phosphorous and Potassium. This combination promotes vegetative growth not flowers and reproductive growth.
For flowers and fruit that Nitrogen needs to be lower in relation to the Phosphorous and the Potassium or you will not get flowers or fruit. When people start using a little of this and that and compost they need to keep track of the amounts of these chemicals (some erroneously call them nutrients...) so they know what these percentages are. Check out your Nitrogen ratios to P and K. Manipulating the day/night hours is tough out of doors so the N-P-K ratio is where I'd start. What have you been using? Chicken poo? Grins! Too high in Nitrogen.
Sometimes all that is necessary is patience. One way to look at these plants is to compare them to an engine starting up. Coughing, spluttering, lumpy running, stop, restart, slowly warming up to a state where it runs smoothly and happily producing fruit. The plant needs to get some leaf area established, a critical amount of biomass established with all the plant hormones and other internals running harmoniously. You don't say how old/large/where the plant is, light conditions, type of soil and so on, so this may not apply but is sometimes the case.