A 10 gallon sounds like an awesome home!
Beside the obvious things like cycling and etc. I would recommend a weaker filter, such as one rated for a 5 gallon because most bettas (excluding the plakat) do poorly in currents.
Some bettas are extremely aggressive, they will happily remove the legs of shrimps for their entertainment. You might want to test your betta reaction before buying a butch. Heavy planting/decorating will help create distractions. Snails that are larger than the bettas head is usually safe because they have a shell. Netrite snails, mystery snails are pretty good choices. If you want other roomies, select something extremely dull and fast.
A lid is a must! Most bettas are great jumpers and their curiousity will leave them flopping on the floor. You can use fish net glued to Pipecleaner.
Some hobbyist use salt and some don't. I always recommend for aq. salt because it can be protect your fish against external diseases. 1/4 tsp per gallon long term can have many benefits.
Live and silk plants are welcomed by all bettas because they love to rest and sleep on them! But make sure you quaratine any new live plants.