What I Learned From Mentoring Startups in the World's Best AcceleratorsRead this if you're a startup in the pre-accelerator phase.

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Besides my day job, I spend many hours each month mentoring young startups in accelerators across London, Berlin, Tel Aviv and the U.S.

I find it fulfilling to absorb the energy in these platforms even when I don't really have time; it inspires me. However, many startups make some common mistakes in their early stages, and choosing the wrong acceleration program or mentors can cause long term damage.

Here are a few lessons I'd like to pass on.

Related:Why the Number of Accelerators Is Accelerating

Don't be swayed by big names

Don't be tempted to sign up for an accelerator simply because a major brand is behind it. Ensure you have all the relevant information about the portfolio of the potential accelerator and the mentors who will be involved before choosing the accelerator that's most suitable for you.

It's true that a major corporation can open doors with respect to client access or even minor funding, but as the saying goes: You can only make a first impression once. There is only one chance in your pre-seed phase, and you must make sure that these perks are all relevant toyourstartup's success and unique direction.

Focus should be the focus

Your young startup only needs one thing that isn't always seen as a priority by all accelerators program managers: focus. You should always aim to know exactly what your product is trying to change in the world, and who your audience is.

It would be a mistake to count only on the marketing coach inside the program to help you, as you never know if his vision is narrow or wide. An ex-CMO of a fintech startup for example, will have great sight regarding financial startups, but a founder of a marketing agency can have sight of more verticals.

Make sure the mentoring sessions offered by the accelerators will be a tailor-made fit for your needs.

Related:Why CEOs Need Mentors -- They Accelerate Learning

Start planning your hiring

While in an accelerator your startup most probably consists of you and a co-founder, you'll quickly learn that your entire product will rise and fall on the staff members behind it. They're the ones building it, shaping it, spreading it on social media, marketing and letting their friends and relatives know about it.

They are the faces of your product.

With that in mind, start planning your hiring as early as possible. Unfortunately, I have seen many startups fail due to bad hiring -- from product to marketing, nothing is more important than a perfect match.

Leaving early

If you rise to stardom too fast, don't hesitate to leave the program early. As much as I am a big fan of startup accelerators, they should adapt for you, more than the other way around.

If your startup is going viral and you feel the time has come for massive hiring and funds, don't lose that momentum simply because you still have a couple of months to go in your current program. Feeling uncomfortable telling your accelerator program manager about dropping out shouldn't stop you from doing what's right for your business.

Related:Thinking of Joining an Incubator? Check Off These 5 Things First.