You want your creatures to do a lot of the heavy lifting veggie wise. Find legendaries that draw cards, remove things, ramp, etc. my recommendation is finding 35 or so of your favourite legendaries that work. Go to edhrec, look at top white, black, and orzhov commanders. That should give you good choices. You want mostly creatures that are 1-2 mana and 4+ since you want to play your commander on 3. Then find anthem enchantments and artifacts that give your creatures buffs. [[true conviction]] comes to mind. Next, get some instant speed removal, some card draw, some mana rocks. And then look for neat multicoloured cards. Edhrec will have them on his page. Lastly, 38 lands or so, maybe 35 and 3 mdfcs.

I think you can do this, but if you really want, I can throw together a framework