How to increase coding ability in smaller models?

I've been running Qwen3.5 35b APEX I Quality to code a piece of software for me through opencode. Are there any plugins/protocols I should be using to give it better coding skills? It constantly messing things up so 90% of the time spent is tracking down issues its created. Also open to using a different model. I've just found this has been the best quality/speed ratio. Currently getting around 30t/s. System specs: RTX 4070 12GB RYZEN 7 5800X3D 32GB DDR4 RAM submitted by /u/keepthememes [link] [comments.