Bookkeeping and the tax stuff to my tax adviser.
I'm unsure on how important that is on other countries but here (in Germany) its incredible important. My first self employment nearly tipped over because I tried to do it myself.
Its important to look for a tax adviser that also does bookkeeping so you can just dump your papers there and leave it to them. They tell you what they need as input (the correct form and timing) and supply you with the information you need on your general finance situation.
Here in Germany the prices for tax advisers are set by government AND tax advisers are legally prohibited from doing advertising (though they can promote themselves on meetings etc.) so to find the fitting one is kind of tricky. You should define what you want from them to do and then ask some if they do so. (If you already know someone who says his adviser is good and fits your need, take the recommended one, its seldom a bad idea.)
Generally speaking, the less clue you have, the more experienced your tax adviser has to be, my current one is a startup-tax-adviser herself and if I would have worked with her when I first looked for a tax-adviser I would have messed it up because she doesn't yet has this calming effect on me as my first tax-adviser had.
Another thing should be that you can reach them with YOUR favorite method of communication. If you communicate by email but they want you to bring your papers personally than don't work with them.
Know the difference between delegating and abdicating.
I delegate a lot of writing and SEO to virtual assistants. Those tasks are the ones that have given me the greatest ROI.
Testing / QA to a small offshore company
Has worked really well for me as its