Hello :0)
1st of all , have fun , its something that can be forgotten and life passes by it regardless.
I would finish and complete the main charactor 1st he has star role and important to not be rusted or not done to perfection.
This included animations ,bones, hud , stamin, health, even weapons, effects etc anything connect5ed to main charactor.
Then after main star is complete , take a pat on the back and grin :0)
Then focus levels design and startup screens stuff as you call it.
Break the tasks into goals.
Complete the main actor but even this can be broken down into mini goals
3d model , texture 3d model , weapon , weapon textures, biped bones for all , import all, setup all, see where im going with this :0)
Breathe write a list of task goals tell your self you WILL be ADDING to the list but always complete the task before moving onward.
Old engineer told me a great true story about an apprentice engineer
Apprentice was taking too long to put the engine cack in the car and so he was called in to the office to answer why.
The apprentice answered he was doing the right thing and not cutting corners to save time he double checked his work so nothing was wrong and ever nut and bolt was correctly tightened up and nipped up tight with washer between.
by checking he was actually saving time becuase the car will not return with any problems.
Another apprentice engineer heard about the slower apprentice and thought im not getting put through that office ordeal and he cut loads of time and corners all the time to make him self look great and yes people did think he was …
Till the day i personally got in my car that had just been in the garage…
Clutch was worn out and needed a new one,could not pull a grape up a hill it slipped that much.
The appentice that tool risks and cut corners to save time had put my clutch in the gearbox and finger tight done up the nuts and bolts on the hold gearbox but he got distracted by something and when he returned to the task he filled it up with oil and FORGOT to do up Tight the nuts and bolts of the gearbox.
I drove off with car fixed and for a day or so it was ok but then a weird noise bumping started as i accellerated i took it in the garage and the last of the bolts lucky for me was the top bolt it was holding the gearbox from falling on the road and then flipping over the car like a pole vaulter uses the pole to jump.
Moral
Go slow , set reasonable / achieve-able tasks and goals , break bigger tasks into part tasks, Double Check then move on.
Hope it helps
If you get time try answering my question its my 1st :0)
Best regards