@ OP: Transitioning often is frustrating (and I speak from experience). Having multiple types of hair on your head makes the growing out difficult enough without adding the chemical changes. My hair is low porosity, and didn't hold relaxers that well, so I had this awful frizzy line on my hair, with little to no curl definition until I hit cheek length with my natural hair. At that point, I called it a day and hacked off the ends.
To one of your other questions, my mother was actually the one who suggested I go natural. (At that point, I hadn't gotten a relaxer in about 3 years).
Okay, so for the actual tips.
1. Moisturize. (You cannot
forget this, or else you will see the worst of your hair... which I assume is not your goal.) It's really easy to get breakage when you're transitioning, so also make sure to treat your ends with care. Protective styling works for some, but I'd just be a little more gentle with them and make sure they don't rub against any sort of rough fabrics/other material. If your hair becomes dry easily, then make sure to use to sealants and/or deep treatments to help with the dryness.
2. Detangle regularly. It's easy to treat your hair "nicely" with moisture protective styling, but you do have to go through your hair every once in a while (frequency depends on the person). When I was transitioning, I detangled once every 3 to 5 days, working out all the knots with a wide-tooth comb. You can finger comb, but I just found it extremely difficult when I transitioned to do so.
3. Trim off damage regularly. Okay, so basically what I mean is, if your ends start to look really straggly or split or just look plain nasty, just start trimming them off. First of all, you're going to cut them eventually, and second, if you leave the damaged parts there, you're increasing the chances that the rest of your hair becomes tangled... In other words, while the point of transitioning is to avoid the "chop," definitely make sure to trim.
4. Keep your scalp clean. I just added this, because having some build-up on your scalp can slow your hair growth (something you do not want as a transitioner). You can either co-wash or low-poo (or I guess poo, but most people's hair can't take that sort of stripping), but do clean. Frequency? Really, it depends. You get a feel for it after a while. I wasn't CG when I was transitioning, so I shampooed about once every two or three weeks. My pre-CG days were awful, but now I co-wash once every 3 to 5-ish days. If you feel like your scalp or hair feels kind of heavy/dirty with build-up, wash. You'll find a pattern in no time.
5. Stay off the heat! IMHO, heat, especially for the transitioner = a lot of damage. You can avoid the damage with heat protectants and such, but I'd just stay off it to avoid the whole ordeal. Yes, you're dying to see your growth and such, but do wait until the dead weight of hair is cut off...
Also, YMMV. Number five is probably the only remotely "subjective" tip, but it makes sense, at least in my opinion. I'd also probably avoid wash and go's for a while, at least, not without the protective barriers of leave-in and oil.
I wouldn't deep condition more than once a week. (I do it once every 2-3 weeks). If you're DC'ing more than once a week, you're not retaining enough moisture (or your DC is not working well), and you should either a) switch DT's or b) do a protein treatment (followed by another DT).
I'm going to add once last blurp about products.
There are no magical products that work on transitioning hair of any age, ethnicity, curl pattern, etc. You really just have to play it by ear. While water is the most important ingredient ever, the other "good stuff" is often what helps keep our hair healthy. You'll have to figure out whether you like thinner oils or thicker oils, protein-free DT's or protein-laden ones, denser products or thinner products, etc. It's all part of the hair journey---that getting to know your hair bit of life.