Thomas Frank's YouTube channel on productivity will help you develop better habits to improve your overall performance for anything and everything. 

For better scholarly searches and sources: https://scholar.google.com/

If you are studying for an exam, enter site:edu [subject] exam in your search engine, and it should pull up sample tests. Take one. 

Check out this YouTube video for a great math trick on standardized tests (how to use the answers!) 

When you want help with complex calculations (or answers on a variety of topics): https://www.wolframalpha.com/

Don't waste paper. Print without the clutter on a page: http://www.printwhatyoulike.com/

Set up multiple timers: http://e.ggtimer.com/

Edit PDF docs: https://www.pdfescape.com/

http://www.polishmywriting.com/

http://kleki.com/

Create mind maps: https://bubbl.us/ ; https://coggle.it/

Ordering something for art class or a project? Track any shipment: http://www.boxoh.com/

Trying to verify a source? https://www.whoishostingthis.com/

https://www.freeimages.com/

Browse cheat sheets for test prep, comprehension, etc: https://www.cheatography.com/

Never hire someone to write a paper for you. You only cheat yourself. You will have to write your own essays on tests; your ghost writer will not be there for it. Master writing skills with help. For creating a bibliography: http://www.bibme.org/ for editing: https://prowritingaid.com/ ;  Power Thesaurus ; OneLook Thesaurus 

Great dictation tool to help speed things up: Talk Typer

Some help/tools/print outs meant to improve memory, reading & productivity at Faster to Master

Professor rankings, test banks, etc.: https://www.koofers.com/

Genius scan app for taking pics of documents: https://www.thegrizzlylabs.com/genius-scan/

Block sites if you are easily distracted/they consume too much time: http://keepmeout.com/en/

Sleeping is key to a successful academic career: https://sleepyti.me/

Game your way to good habits: https://habitica.com/static/home

DIY tutorials: http://www.instructables.com/

Research/video help: http://www.jstor.org/ ; https://www.youtube.com/user/crashcourse ; https://universitywebinars.org/

Math tools: https://teacher.desmos.com/ ; https://www.khanacademy.org/ ; http://www.searchonmath.com/

Try various search engines for specific research needs: ZapMeta ; Yippy ; AltaVisaAdvanced ; Librarians Internet Index ; Google Advanced Search ; Teoma ; Infoplease for biographies ; VirtualLRC ; World News Network ; search for/by headlines ; international directory of search engines ; CIA World Factbook ; more headlines US & world ; help with research statistics ; Smithsonian libraries ; UNESCO resources ; CNET ; 28,000 quotes ; repositories of primary resources ; public radio ; 

The Canny Link directory, which helps you find just about anything for research purposes, teaching, etc.