Unfortunately, without knowing what kind of plant this is, it is difficult to give you advice. Both overwatering and underwatering can cause yellowing and browning (most plants like soil that is evenly moist yet well drained, meaning damp like a wrung out sponge -- not sopping wet/saturated and not dried out). Overfertilizing can "burn" plants and cause similar symptoms (never use more fertilizer than is listed on the label directions). Placing a shade loving plant in too much direct sun, exposure to cold and frost damage, and even transplant shock can cause problems, too. I'm sorry I can't be more specific for you.
You must be signed in before you can post questions or answers. Click here to join!