Shooting can really tear chunks out of Ogres, mainly because even though they are toughness 4 they have little to no armour. Just be wary of any gorgers as they can be a real pain and are more than a match for war mahcine crew and can even nail missile units. Most Ogre armies play MSU so field units of about 3 - 4 Ogres, if you can cause 3 wounds, then its a panic test. Also, the loss of 1 Ogre can really hurt a unit as they lack static combat Res so need all the hitting power they can to break through. Robbing them of one Ogres attacks by killing him can seriously give you the upper hand.
Due to the lack of armour Ogres are also very vulnerable to poison so I would heavily advise taking a unit of Witch Elves. If you have a six wide frontage and you get the charge that means you can get off 19 poisoned attacks if you have a champ (20 with the rune of khaine).So you stand a good chance of dropping one whole Ogre before you even roll to wound. Also, the fact that they are Immune to psychology means they will never fail that crucial fear test.
Take plenty of Dark Riders. One of Ogres main strengths is their speed, if you take things that can outmanoeuver them then they are at a disadvantage. Also, they tend to be great at moving in a straight line but struggle if you get on their flanks or behind them. Hitting them in a flank is a great idea because even if your rolls are terrible only 1 Ogre can attack, as opposed to 3 or 4.
Magic can be good but be wary of characters in units as they can take some great anti-magic items.
If he takes leadbelchers, be very wary of them as one round of shooting can annihilate a whole fast cavalry unit (trust me - ive seen it happen
). So try to eliminate them before then can shoot.
Chariots might be good, they can charge further than Ogres and the impact hits could be very devestating. Again, there is no chance that they will fail that crucial fear test. (they may fail their stupidity test instead mind)
If he takes a scraplauncher, you can bait it as it has to take a LD test or charge a viable target. A good plan is to use shades (or any fast unit) to bait it into a wood, because it is a chariot, it can often damage itself as it charges headlong into the terrain.
Remeber Gnoblar trappers - they are scouts. Even though they aren't very good, if they appear near to your bolt thrower then can really annoy you early on - but some careful deployment will prevent this.
Harpies low leadership means they will rarely be fighting Ogres but they can charge any annoying gnoblar trappers, march block or even be used to lure away a gorger - as they have to charge a unit if they can.
Dont rely on being able to take a charge with a large unit of spearmen - even head on. Ogres hit like an tank and its frightening how much damage they can do - especially if he has any combat characters in the unit or they have been boosted by Gut Magic.
Overall advice - take witch elves, out manoeuver him, charge him - dont ever let him charge you, shooting works wonders - take out leadbelchers early on. Hope this helps and good luck next time!
Hope this helps