Ogre Starter Army (2000 Pts)

I am new to ogres as of yesterday. I have played against them many times but never lead an ogre army. I traded a small skaven army for a small ogre amy and need help knowing how to expand. 
This is my army so far:

Core
8 Ironguts
4 Bulls
45 Gnoblars

Special
1 Gorger
4 Mournfangs

Rare
2 Ironblasters

My question is what do I need to focus on adding to make this a competitive 2000 and 2500 point army.  Obviously I need characters. I was thinking about converting a BSB and getting a slaughtermaster but I don't know if a Tyrant is needed as well? I like the idea of the bigger models and would love to work in a stonehorn or thundertusk. Also the gnoblars I have are from the irongut kit and I don't know if these will really make a usable unit. Any help is guidance of where to go from here would be appreciated.

Thanks
Rivvin

Getting a hold of more Ironguts and Bulls would be a good start for your core. You have more than enough Gnoblars. As for heroes I personally run mostly a Slaughtermaster and a BSB. For 3K I might use a Tyrant. Add some Leadbelchers for some added punch and/or Maneaters (which I like a lot). But beef up your core and add the heroes and you should be good to go.

 You have a good start on things though, 4 Mournfangs 2 Ironblasters, good stuff to have.  I'm starting to dislike the Stonehorn/Thundertusk. They get killed off really fast and makes me sad that they die before even seeing combat. More than enough people have success stories with them so don't count them out.

Thanks for the advice. How many Bulls and Ironguts do you suggest per unit? I was thinking units of 9? And 2 units of 4 leadbelchers? Seem like a reasonable place to start with purchasing new models?

How would this look? (and start adding leadbelchers to get to 2500)

2000 Pts
Lords
Slaughtermaster- Grut's Sickle, ironfist, armor of destiny

Heroes
BSB- HA, ironfist, fencers blades, talisman of protection

Core
8 Bulls FC
8 Ironguts FC
36 Gnoblars

Special
4 Mournfangs FC HA, Ironfist,  Dragonhide Banner

Rare
2 Ironblasters

That's not bad at all. For the bulls are you taking IF? With your SM (this is just personal but) has armor and to me it takes away from the spirit of the game. Do what you want to do but some people may give you the stink eye. Do the Gnoblars have traps? Dragonhide banner on the Mournfang is great but also risky. Reason being is that you have to win the combat because you loose and turn tail and run your standard bearer is just gone. I don't take Standards in the MF unit. If you can beef up the Bulls and Ironguts just a bit that would be great but not a bad start at all.  If so great! Very competitive as is.

Sabertusks are great cheap diverters and movement 8! I bought space wolves that come in packs of 5 and gave them the right base. If you want to save some cash. Butchers and sms are fairly easy to convert with green stuff apron.

I started using tyrant in all my lists even with a sm. (2500p).

When i started playing i had one big block of bulls and one block IG. I found that the bulls did not perform so well. Now i use them as 3 man darts/divert/support and find more use for them. Also helps in deployment.

As for the big beasties. Sutch a cool model, i got mine magnatized so i can have it as a stonehorn or thundertusk rly cheap. At first i only used stonehorn but lately the always strike last aura and mobile stonethrower thundertusk fits well in. With 2 ironblasters (if you can and not play comp) you should be able to handle their cannons before they get to the tusky.

As for leadbelchers, i made 8 and use 4 - 6. Oh well. Great for clearing chaf.

Maneaters are strong units and versitile. 6 maneaters demolished 40 halibearers and the support of weather wagon.

Last but not least, welcome to ogres.

I would not complain about the SM having armour, a 4+ armour save is nothing to brag about. You could also do Talisman of Preservation + Ironcurse Icon or something. I would cringe more at double ironblaster as cannons are very powerful.

I would give your BSB Talisman of Preservation, Ironcurse Icon and a great weapon.

A tyrant is a great fighting character, but he will cost around 350 points. For that cost you could also get a unit of over 8 ogres with command and Ironfists...

2 units of 4 leadbelchers is great for some ranged power. I myself would not run Maneaters with pistols, as they have poor BS and pistols aren't that great. I see most people run Maneaters with poison + sniper + brace of ogre pistols on everyone, but I prefer to equip them with melee weapons. Maneaters have amazing S, so I think using them for shooting is a waste of their skill. True, they aren't very durable with only heavy armour, but you can cast Trollguts on them and their damage output is insane compared to any other troops.

Unit sizes should be planned with the inclusion of characters. If you want a unit that can take pain and hold their ground you want ranks, so make your unit 3 wide, so 8 ogres + character for 3 ranks, or just 9 ogres.
If you want a unit that gives tons of pain, you want a horde. 6 wide, so atleast 18 ogres to benefit from the fact that an extra rank can attack.

And yes, get some sabretusks. Amazing diverts and great war machine hunters.

Thanks for all of the great advice and welcoming comments. I am glad I asked before I started to increase my army size. It sounds like there are a lot of little things I can adjust. I was thinking about keeping the BSB as defensive compared to offensive with a GW. The other ogre do some damage and I really want to keep him alive. Does this look better?

2000 Pts
Lords
Slaughtermaster- Grut's Sickle, ironfist, armor of fortune, Ironcurse Icon

Heroes
BSB- HA, Enchanted Shield, talisman of preservation

Core
8 Bulls FC LG
8 Ironguts ironfists FC LG

Special
4 Mournfangs FC HA, Ironfist,  Dragonhide Banner
Sabretusk
Sabretusk
Sabretusk x2

Rare
2 Ironblasters

Get points for Standard of Discipline in your Irongut unit. Drop out one of the sabertusks in the unit of 2, there's not really any benefits to making bigger units than one. This way you will get a LD9 general (if, and when you put the SM with the Ironguts) without taking a tyrant. BSB is great, if you want him to stay alive as much as possible that is the way to go.
I would give the SM the armour of Destiny for a 4+ ward.

It's quite a nasty list with 2x chariot cannons, Level 4 with +6 or even +7 to cast and a big plow of mournfangs with the Dragonhide banner.

So I will keep incorporating advice until it stops coming. Here is the most recent list. I am torn on using armor on the SM fluff wise but my local meta is pretty competitive. Thanks for all of the help

Lords
Slaughtermaster. Lv4. IF, Armor of Destiny, Grut's Sickle

Heroes
BSB. IF, Biting blade, Armor of Fortune, Ironcurse Icon (I face a lot of vampire ethereals hence the magic weapon)

Core
8 Ironguts FC Standard of Discipline
8 Ogres M, S, IF

Special
Sabretusk
Sabretusk
Sabretusk
4 Mournfangs M,S Dragonhide banner

Rare
Ironblaster
Ironblaster

You are missing a dispell scroll. Consider dropping one IG and some bulls, maybe even a sabertusk to get a firebelly with scroll (for fireball sniping chaf) or a butcher lvl 1 with beast or heavens for nice signature spells.