Here's a list distilled from past posts and other sources:

Attack: Ionsaigh
Attention: Aire
Avoid: Seachain
Back: Gabh 'niar
Bad dog: Madra dána
Be careful: Bí cúramach; Fainic
Be quiet: Bí ciúin; Ciúnas; Ciúnadas
Beware: Fainic
Bite: (Beir) Gréim
Bold dog: Madra dána
Bravo: Maith thú
Car: Carr; Gluaisteán
Careful: Fainic
Come (here): Goile; Tar anseo
Come in: Isteach (leat)
Come with me: Tar liom
Cross (the road, etc.): Trasnaigh
Dinner: Dinnéar
Don't be Naughty: Ná bí dána
Door is closing: Tá an doras ag dúnadh
Drop it: Cuir síos é
Easy: Tóg go bog é
Fetch it: Faigh é
Follow it: Lean é
Get down (off my lap, etc): Gabh síos
Get down (off the sofa, etc.): Gabh anuas; Anuas
Give it to me: Tabhair 'om é
Give me your paw: Tabhair 'om do lapa
Good dog: Maith thú; Madra maith; Maith an madra
Good on you: Maith thú
Have a care: Fainic
Heel: Sáil
Here you are: Seo duit
Here (when tossing food or ball to dog): Seo
Here: Anseo
Inside: Isteach
Jump: Léim
Leave it: Fág é; Éist leis
Leave me alone: Éist liom
Left: Ar chlé
Let it go: Scaoil é
Lie Down: Síos; Luigh síos
Listen to me: Éist liom
Look at me: Breathnaigh ormsa; Amharc ormsa; Féach ormsa
Look: Breathnaigh; Amharc; Féach
Naughty dog: Madra dána
Off with you: Imigh leat
Off you go: Imigh leat
OK: Tá go maith
Onto the footpath: Isteach ar an gcosán
Out(side): Amach; Amach leat
Out you go: Amach leat
Paw: Lapa
Play dead: Marbh
Put it down: Leag uait é; Fág síos é
Quiet: Ciúnas; Ciúnadas
Relax: Tóg go bog é
Right: Ar dheis
Roll over: Cas thart; Iompaigh thart; Cas timpeall
Search: Cuardaigh
Shake hands: Croith lámha
Show me your paw: Spáin 'om do lapa
Silence: Ciúnas; Ciúnadas
Sit down: Suigh síos
Speak: Labhair
Stay: Fan
Stop: Stop; Stad
Take it easy: Tóg go bog é
That’s good: Is maith sin
That’s it: Sin é
There's a car coming: Tá carr ag tíocht
There: Ansin
Toilet: Leithreas
Up (from the ground): Aníos
Up (to a high object): Suas
Wait: Fan
Walk: Siúil
Watch out: Fainic

_________________
Múinteoir Gaeilge - Irish Teacher
My "specialty" is Connemara Irish, particularly Cois Fhairrge dialect, but I can also speak Ulster and Munster Irish with native-level pronunciation.
Is fearr Gaeilge ḃriste ná Béarla cliste, cinnte, aċ i ḃfad níos fearr aríst í Gaeilge ḃinn ḃeo na nGaeltaċtaí.
Gaeilge Chonnacht (GC), go háraid Gaeilge Chois Fhairrge (GCF), Gaeilic Uladh (GU), Gaelainn na Mumhan (GM), agus Gaeilge an Chaighdeáin Oifigiúil (CO).

Lovely, thanks mate. My cousin has a couple of Irish Wolfhounds. Maybe if he uses these they'll pay better attention.