I'm pro-new-species, particularly the background kind (that have enough detail to show up in the RP but not necessarily the level needed to play) so long as they're not of the "Yet Another Human-Looking Species" since we have a lot of human-looking species already, ala Star Trek. So there's one thing you've already got covered. We have a species/faction creation guide
here that goes pretty in-depth with advice from over the years.
So, for starters, here's what we need for the foundation of a new species:
1. Where are they from? If they have a planet, let's make an article for it and the star system it is in. The planet probably will influence their biology.
2. What are they? We'll need a article for their biology. A pencil sketch or a basic MSpaint drawing etc. would be a great starting point to help visualize them. If you want to go further than that but you're not great as high-end art, consider using a 3D modeler, like the super-easy-to-use
DOGA. For the text, thing about where their organs are, how they see, eat, communicate, shit, etc.
3. What are they up to? Articles for culture and for their government will show what they want and how they think.
With the above, you're pretty much set for submitting for approval. With the addition of some core technologies, it should be about all you need to start with and from there you can just keep building, making new articles as inspiration and need hits...creating your own take on everything from medical kits to education systems.
I guess the next big question is: Are these supposed to be a player faction or are these a background faction? The difference is for player stuff we expect teamwork and background factions can be made solo.