In regards to your first question, since you’re not satisfied with answers of ‘do what you like’ I’ll just say
Strive to have high quality observations. Sure, not every picture is going to be good, and sometimes you can get a good id off of a bad picture (especially with birds and mammals) but there are some taxa that are REALLY hard to ID without good pictures. Many plants (especially in Asteraceae) are really really difficult to ID without pictures of the right morphology (often when they’re not in flower, you just can’t, unfortunately,) and many fungi ARE ideable but people just post a single picture from one angle and the pictures are missing key identifying features.
So say you come across a flower you’re unfamiliar with; take pictures of the leaves, the undersides of the leaves, the stem, the flower, a pic of the flower from the side, a picture of the bracts… etc. Get every angle, is what I’m saying.
If you have a fungus, don’t just get a picture of the cap. Take an in situ shot. Pick it (or at least angle your camera so you can get multiple angles), take a picture of the stem, the gill attachment (if it has them,) the base, note what the substrate is and what trees its growing around (deciduous or coniferous?) Smell it, what does it smell like?
Stuff like this will help improve the quality of what you’re seeing.
Regarding how to find projects - honestly just get on projects, type some keywords you’re interested in, and start looking. Users aren’t allowed to advertise specific projects in the forums (unless related to an ongoing discussion,) so you’re really not going to be able to find them out here. That said, I will call out this site (https://mycota.com/2023-continental-mycoblitz/) which is one of the groups in NA involved with fungi DNA sequencing and while the fall mycoblitz just ended, I’m sure he’ll run some more in 2024. You know, if you’re interested in fungi.