#2 – Hang some string lights
Nothing makes an evening more special than sitting under special lighting such as string lights! If you want an old school feel, use classic round bulb globes with a low light around 40W, which will give a soft “candle feel” to your backyard.
Another option is fairy lights, these are often brighter and give you the ability to alter the ambience depending on the lighting function on the lights that you choose. These are easy and inexpensive to install for any occasion.