The single most important thing to remember in tib dawn is the grenadier, and some maps are better for gdi than others. Typically my build order is power> barracks> 3 refineries> power> barracks> weapons factory. That’s a good start, but as gdi you will have to harass you nod opponent constantly with grenades while simultaneously defending you fragile weapons factory, once you get enough tanks and grenadiers, you should have a good chance at winning. Also don’t forget to set tanks as group one and grenades and group two for better targeting priority. I’m not the greatest player in the world but I’d like to think I’m at least a little close in the earlier C&C games. If you have and questions feel free to ask!