My suggestions:
1-A good carrying bag. There aree so many options, think about what you will carry, how you want to carry and use your stuff, etc. I have tested many many bags and can give pointers if you wish. I particularly like Think Tank and Peak Design, but there are other great products.
2-A decent strap. I use Peak Design's system, but rarely use a neck strap, I prefer my custom-made hand strap built from a strip of leather and Peak Design's Anchor links.
3-A tripod. Do not cheap on this, get something good or you will spend more money upgrading. Size, stability and price do not mix well, you can usually get any two.
Travel tripods are not the same as studio tripod.
4-A flash. A good P-TTL flash with slave options is a good choice. I like Metz's 52 AF-1, not too expensive, quite easy to use and intuitive, powerful and reliable.
5-Lenses. decide which kind (s) of pictures you want to take, and you will be able to get guidance as to which lenses could be a good fit.