Check out the stickys. Trevally's Mod Guide for Beginners and Sobers Mega Mod threads are both very helpful.
Sober also has tips about starting a campaign and disabling U-Play's online mode and the "silentotto" cheat to unlock all campaigns. I was getting frustrated with U-Play disabling my mods and having to start new campaigns over at "Coastal Waters" every time I changed my mod soup. Thanks to sober, I don't have those problems anymore.
If I were "baby-stepping" into SH5 mods, I would start with
1. NewUIs_TDC_7_1_0_ByTheDarkWraith
2. DynamicEnvironment 2.9
3. Open Horizons II
I am really happy with my current soup 04042013:
German U-Boat Crew Language Pack -
Not in Sobers MM
Accurate German Flags
DBM Background Video
SteelViking's Interior Mod V1.2
SteelViking's Interior Mod V1.2.2 Patch
Dark_Interior_V1 -
Not in Sobers MM
DynEnv v2.9 - 1. Main Mod
DynEnv v2.9 - 5.a Ambient Settings - Darker Nights -
Not in Sobers MM
DynEnv v2.9 - 8.b Wave Mechanics - Gale -
Not in Sobers MM
DynEnv v2.9 - 10.II Seafloor (medium resolution) -
Not in Sobers MM
DynEnv v2.9 - 11.a.II Sea Plants - Atlantic Kelp Forests (medium resolution) -
Not in Sobers MM
DynEnv v2.9 - 11.b.II Sea Plants - Med Posidonia Meadows (medium resolution) -
Not in Sobers MM
DynEnv v2.9 - 11.c.II Sea Plants - Coral Reefs (medium resolution) -
Not in Sobers MM
DynEnv v2.9 - 12. Sounds
DynEnv v2.9 - No Underwater Impurity Patch -
Not in Sobers MM
SH5_7A_Conning_Fix
Fuel Gauge WoGaDi_SteelViking's Interior
SH5 Longer Repairs v.1_Stock
FX_Update_0_0_21_ByTheDarkWraith
NewUIs_TDC_7_1_0_ByTheDarkWraith
NewUIs_TDC_7_1_0_alt_officer_wounded_by_Torpedo
NewUIs_TDC_7_1_0_Real_Navigation
Manos Scopes-patch for 16x9
IRAI_0_0_39_ByTheDarkWraith
IRAI_0_0_39_ByTheDarkWraithPATCH1
Depth_Keeping_Problem_HB_2_0_0_TheDarkWraith -
Not in Sobers MM
TheDarkWraith_DC_Water_Disturbances_v2_0_SH5 -
Not in Sobers MM
TDW_No_Hydrophone_On_Surface_No_Aircraft_Spotting_ 1_1_0 -
Not in Sobers MM
silentmichaels interior mod 1.2.1 BASEGAME
SubFlags_0_0_8_byTheDarkWraith -
Not in Sobers MM
OPEN HORIZONS II_full v2
TDW_Mines_Subnets_Detectable_in_hydro (OH II v2) -
Not in Sobers MM
No magic skills v1.5 -
Not in Sobers MM
MightyFine Crew Mod 1.2.1 Alt w beards
MFCM 1.2.1 OPTIONAL crash_dive workaround -
Not in Sobers MM
Harbour_Mod_Hans_reworked_for_OHIIv2_by_Trevally -
Not in Sobers MM
OH II Minefield map for TDWs Ui
Stormys DBSM SH5 v1.3 Basemod -
Not in Sobers MM
Stormys DBSM SH5 v1.3 optional -6db damped Sonarguy -
Not in Sobers MM
Stormys DBSM SH5 v1.3 optional NavMap babelling -
Not in Sobers MM
Stormys_DBSM_additional_creaks_and_noises_1.0 -
Not in Sobers MM
Stormys DBSM SH5 v1.3 HOTFIX 3 -
Not in Sobers MM
Stormys DBSM SH5 v1.3 additional crew sounds beta6 -
Not in Sobers MM
Default Keybindings for Stormys DBSM -
Not in Sobers MM
^hey look it's my tiny little mod for SH5!!!
DBSM_Music_1_0_4 -
Not in Sobers MM
EQuaTool 01.01 by AvM - Large Style
Trevally Tutorial - All v0.2(for OHIIv1.3)
Trevally Automated Scripts v0.6
Trevally Harbour & Kiel Canal Pilot v2.9
Trevally TDC Help v2
MadMaxs_SH5_Subdiesel (mono) v2
Messervy_s_gramophone_pack1
Grossdeutscher Rundfunk
AST_SH5_v2
Nauticalwolf's_Damage_and_Torpedo_UI(b)_Mod_v1.1 -
Not in Sobers MM