Hey Charger!

I haven't reviewed anything in years, but I'm going to give this a go. All in all this is a pretty solid first attempt at a showcase! I'm going to list some points for improvement down below.

Clean: Not quite. Your file contains edits to the 'evil GMSTs' which need to be cleaned (this is not your fault, per se, the construction set seems to always make these edits). Also, it seems bk_MysteriousAkavir and light_de_candle_03_64 have been changed, those need to be cleaned, too.
Ambient/Fog/Sunlight: I think these are currently still set to defaults. If you to 'World' then 'Interior Cell' and select your cell, you'll see that your ambient lighting is quite grey, and that your sunlight values are very high. Compare this to some vanilla Hlaalu style interiors and try to find appropriate values - just check out a couple of Balmora interiors and you'll get the hang of it.
North Marker: Yes, good.
Dependencies: remove the TR_Mainland dependency, only have your file depend on Tamriel_Data and the vanilla .esms.

General remarks: Judging by the position of the door, I think this building is made for a ex_hlaalu_b_05 shell. However, ints for those are typically 2x3, not 2x2. Shells for 2x2 do exist, like ex_hlaalu_b_04, but the positioning of the door is off. In any case, I think it's a good idea to slightly expand the shell, adding two more tiles in the north, so that it's 2x3 and you have some more space to show off your skills!
Interior is a little sparse. Try to aim for 100 references, to make it a bit more lively. That might be a bit high for a lower-class house like this but it'll give us more opportunities to assess your skills!

Specifics: 
in_hlaalu_room_corner in the southwest: be sure to check the grid snapping of your tile pieces. Your is slightly offset on the X and Y axes, so there's a tiny gap between this and the other pieces!
in_hlaalu_doorjamb: this should be used for doors with interior on both sides. For load doors like this one, use in_hlaalu_doorjamb_load.
com_chest_01_misc05: not a positioning problem, but the com set is a little out of place among the de_p furniture. Perhaps a de_p style chest would be more appropriate. It's not entirely unrealistic to have some style mixing though, so I'd let it pass.
sc_paper plain on the table is floating a little bit. This is one of those annoying models that doesn't quite work with the F key - press once and it floats, press twice and it z-fights. My suggestion, press F twice and then raise it a tiny amount.
gold_001, twice: stuck in the middle of the table, unreachable.
misc_com_silverware_spoon: again, mixing styles a little bit. Can be lowered into the bowl a bit further. Speaking of the bowl, that one is placed very well!
Furn_de_rug_big_04_Collision can actually be bled into the floor a little bit - so that the frills on the edge are closer to the surface. Select it and everything on top of it and lower it a tad.
furn_de_p_table_02 is empty, put something on it?
furn_de_p_bookshelf_01 and friends: overall you've done a good job rotating items to match the (annoyingly warped) de_p furniture!
bk_MysteriousAkavir could be adjusted a fraction at the high side
sc_paper plain on the shelf, the bottom one is bleeding into the shelf a little, while the top one might be a little too far above the bottom one, but that latter remark is within acceptable range, I think.
T_CyrImp_Furn_ChS1Potion: you did a good job trying to adjust this one to the surface but it's currently a little awkwardly balanced between two vertices. I would suggest moving it a bit more to the middle of the top shelf, where the candle currently sits, so that you don't have to adjust for two surfaces simultaneously and don't have to bleed it in the middle.
bk_BriefHistoryEmpire1 through 4: good job varying the stacking/placement. It should be noted that in vanilla, finding a complete series of books is fairly rare (thoug for Brief History it seems more common), so you might want to consider adding just two or three of these, especially in a poor house like this.

Conclusion:
Like I said, solid effort! Don't let this list of things-to-improve discourage you. It is clear that you have the right idea, and that you've read the guidelines, judging from things like the proper sinking of the bowl, and the great effort at rotating things on the de_p shelf. I'd encourage you to stick with it, to fix the above issues (insofar that they are issues, anyway) and to expand your interior by two pieces in the north, so it properly fits an exterior shell. Then add a tad more detailing, like I said, try to hit a 100 refs, add some clutter to the nightstand, and resubmit!