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

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WARNING: Intermediate speaker - await further opinions, corrections and adjustments before acting on my advice.
My "specialty" is Connemara Irish, particularly Cois Fhairrge dialect.
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), 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.