Your board is read in a noisy room by someone standing two metres away who will give it eight seconds before deciding whether to stop.
Structure. Three columns, read top-to-bottom then left-to-right. Title band across the top. Question top-left; conclusion bottom-right, where the eye finishes.
Text budget. Under 500 words on the whole board. Title readable at 3 m (about 72–100 pt), section headings at 36–48 pt, body at 24–28 pt. If your body text is under 20 pt, you have too much text, not a font problem.
White space. Aim for roughly 40% empty. A dense board reads as unconfident, and nobody reads it.
Figures carry the argument. Three to five, each with a caption that states the finding — "Fig. 2: biomass increased with nitrogen up to 100 ppm, then plateaued" — not just "Fig. 2: biomass by treatment". A judge who reads only your captions should get your whole result.
What to cut, in order: the full methods paragraph (keep a diagram), the literature review (keep one sentence), raw data tables (keep the summary), and any figure that does not change what the reader believes.
Print a draft at least a week out. Errors that are invisible on screen are obvious at full size.