Birding in the Seychelles is not particularly productive outside of the endemics and seabirds.
On Mahe the main spot is La Misere (check ebird for location and lists of what is seen there), as this is THE spot to see Seychelles White-Eye, and you'll get several other endemics there with little effort. The cross island road that passes the Mission Lodge View Point is another key spot. At least on my visit in October of 2017 Seychelle's Kestrel was reliably coming to roost up inside the roof of the view point structure just at dusk. From the view point down hill to the north is the best area of road to work at night for Seychelles Scops-Owl, ebird will show you locations again.
Praslin is good for Seychelles Parrot, best spot is standing in the car park of Vallee de Mai Nature Reserve and waiting for flyovers or perched birds. Easy and reliable mornings and evenings.
La Digue is the spot for Seychelles Paradise-Flycatcher, there is a particular track to the beach that makes a lovely hike and they're generally easy along there. ebird will point you at specific locations again.
Aride is a very nice visit and is the best and easiest spot to get three remaining endemics - Seychelles Warbler, Seychelles Magpie-Robin, and Seychelles Fody, along with a ton of nesting seabirds. I had a lovely time and wouldn't leave it out. For anyone who is much of a lister, Aride is an absolute mandatory visit. As I recall you need to arrange your own transport to the island and arrive on time for the start of the tour or you miss it. On the way back from Aride have your boatman drop you at Anse Lazio, a lovely beach with some of the softest sand on the planet, and have some beers at the Honesty Bar, far end of the beach and up under the trees. Just lovely.
All of the endemics and a good selection of seabirds can be found on just those four islands - Mahe, La Digue, Praslin, Aride. By far the hardest endemics are the White-Eye and Scops-Owl, and the Kestrel could be tricky if it is not coming to roost at Mission Lodge View Point. The rest are pretty mellow - just go to the right places and you should find them all.
Cheers and enjoy!
Josh