If you plan to spend the night when you arrive in Mahe, it is best if you can book your hotel before you land at the airport. If you do not have a booking, but can prove that you have funds, you'll be asked to book at the hotel booking counter right there. You get to stay for as long as you have a booking only. No looking around after you arrive!
Fun Alternatives: Book and pay for your hotel before you leave home.
Even if people at travel agencies are very nice and always available if you have questions or need something, it is better to try and find your trips by yourself, you will get a much better price. Take the bus or rent a car and circle around the island. Boat trips to La Digue and Praslin are expensive too if you ask agencies. Just take the boat to those islands and go by yourself.
If you want to rent a car, don’t ask your travel agent or you hotel, the price will be higher too. You will find a lot of car rentals in Victoria where you can get better prices.