Igor's top 10 tips for growing your hair

#10 Never put something in your hair that cannot dissolve in water
I'll start off with a simple one, one that has saved me quite a bit of trouble over the years: Never put something in your hair that cannot dissolve in water or conditioner. No matter how experiment-happy you get, no matter how praised the DIY treatment is, just don't do it. Yes, that oatmeal-treatment does look awesome. Yes, the post treatment-shot of that banana-treatment looks amazing. Just don't do it. If something can't dissolve in water or conditioner, don't put it in your hair.
You risk ending up smelling like slowly rotting banana for days. The stories are out there on the forums, often buried deep on the topic lists: No one likes those horror stories, and people often don't write about them. But they do happen.

#9 Know your growth rate
This is an important one if you want more length: You need to know exactly how much growth you get, so you know exactly how much you can take off to keep your ends smooth and healthy. It's so easy to fall for the wisdom of tips like "You need to take off 1 inch every 6 weeks to keep it healthy", but if your hair doesn't grow that fast you can actually end up with minus growth.
(In my case, with 1,5 cm every month plus 2-3 months in the summer with 2 cm, I get 12x1,5 + 3x0,5 = 19,5 cm of growth. (52/6)x2,5 =21,6 cm, which would mean that with the above tip, I would end up with minus 2 cm of growth in a year.)
How you actually measure isn't the most important. What is important is that you do it the same way every time. Write it down, keep track and know your seasonal variations.

#8 Get your trims
This is a twin tip to #9. Trims are important. You need to get rid of damage: It affects the healthy hair because you need more handling to detangle, it develops/spreads and causes damage to the healthy hair surrounding it.
Don't be afraid to trim, it's one of the easiest ways to make your hair feel awesomely smooth and healthy. There are many methods: Micro trimming/dusting, search and destroy where you look for individual damage and snip the problems you find, and simply cutting all ends sticking out of a braid, just to name a few. A trim doesn't have to be big to have a big effect, just a few millimeters can make a difference.

#7 The value of products
There are really only so many things you can actually do to hair with products and ingredients. Keratine, 'cones, panthenol, oils and plant extracts just to name a few that often gets highlighted on a product. Some will have an effect, some won't. But most of the time, the specific ingredients themselves doesn't have a big effect.
You simply can't "rebuild" hair in the way that commercials wants you to believe.
What you can do is shield and protect your hair from damage. Products is where you can save serious money: Often a cheap product is every bit as good and makes your hair look awesome as an expensive one.
When you really want to squeeze more effect out of your product, you should look into different washing methods or generally make your deep conditionings longer.

#6 Leave ins are love
Another twin tip, this one to #7. Although there is only so much you can do with your products and ingredients, leave in products can do quite a bit: They can make your hair smoother, so you can comb tangles out with less force. They can allow oils a long time to penetrate your hair. They can offer some hold and make your updos stay prettier for longer. They can add shine. They can add SPF and protect your hair from UV rays. Leave ins are great!

#5 Check your tools
When buying things for your hair, you will often find terms like "Hair friendly!" plastered on them. This means absolutely nothing. There are no regulations for the quality for tools and items for hair. So look thoroughly for seams and sharp edges. One single sharp seam can rip and tear your hair, and worst of all: Take a long time for you to discover. Feel your tools everywhere you can: If something is sharp enough to scratch or hurt your skin, it will damage your hair. Take sandpaper or even a nail file to all edges that touch your hair just to make sure.

#4 Knowledge is power!
Advertisements love pseudo-science. Advertisements love telling your that this new, unique, totally exotic extract in this amazing product will definitely make a difference to your hair. Having the most basic understanding of what hair actually is, and what you can actually do with it, will help you avoid those traps. Wikipedia will do fine, but I'd encourage anyone to open an anatomy-book.
This also goes for knowledge on what works for your own, unique head of hair. Not everything works for everyone. If you know something makes your hair a tangled mess, or something causes closed comedones on your scalp, never let anyone convince you anything else!

#3 Motivate yourself through your hair
Eating healthy, getting exercise, avoiding alcohol, not smoking, sleeping well, avoiding stress. We all know this stuff. Diabetes, lung diseases, cancer, osteoporosis, pulmonary disease, strokes. We all heard about the risks so much it makes us deaf to them. The "Be healthier!" resolutions are all so big, somehow vague and hard to relate to.
How can you relate to that not eating enough fruit can increase your risk of xyz if you're over the age of zyx by yzx %? You can't.
But knowing exercise increases your blood flow and may increase your hair growth? Or that eating healthy avocado supplies you with healthy oils that are good for growing healthy hair? Or that sugar breaks down the collagen in your skin? It's so much easier to relate to. So much more understandable. And it motivates.

#2 Find your minimum effort
The thing that most people struggle to understand is that it takes an effort to screw up your hair. Leaving your hair mostly alone, just washing it when needing and then putting it up, is so much less effort than all the fancy treatments with the trendy buzzwords, the "totally damage free!" straightener, that one brush you can totally use on wet hair and all the organic, natural kitchen witchery you found on Pinterest.
Finding that minimum effort is where the magic happens.
This is why benign neglect is praised and preached. It's simply the way to go if you want to grow your hair long and/or healthy.
Finding the minimum effort is also where you won't suddenly find yourself frustrated with how time consuming growing your hair is, and cutting it all off in frustration. Repeat cycle ad libitum.

#1 Blog!
Blogging is such a good tool for a lot of the tips mentioned above, which is why it's my tip #1. Use it to keep track of your growth rate, your trims, the products you like and dislike, your experiments, your tools and routines. Use it to motivate yourself, to focus on the cool updos you can do in the future with just a little more length. Use it to log the styles you do, so you can always go back to find the updos you like if they should slip from rotation. Use it so you can always go back to a routine that worked for you, if you should have strayed too far into DIY's and experiments. Keep track of things that doesn't work for you, so you won't fall for the temptation to try it again. Save your links and inspirations in your blog.
Have fun with it, do it for yourself, but remember you can also get a lot of interesting feedback from your readers!