My design process:
This is MY design process. I am just stating what I do, so others can ignore this or laugh at it, or trial it.
On a side note, when I first started out, I quickly learnt that I needed to research what the best method/times was for each genus I was working on.
In other words, determining the best time to perform a significant cut-back for a particular species... researching how much foliage / root you can safely remove at repotting time / cutting back etc etc. If I had asked members more of these important questions 20 years ago it would have greatly improved my successes initially.
But the following is pretty much how I roll...
1. I go to a bonsai nursery / nursery. (the advantage of visiting a bonsai nursery is that the stock has been continually cut back and root pruned over the years, so once you get stuck in, the shock on the tree is usually less on the more advanced material).
2. Critique the tree BEFORE you buy it. This is THE MOST important moment in the trees life. You need to spend the most amount of time and effort at this point. Look at the main trunk and lower branching and decide if you are happy with this. Obviously you are better off buying something with movement you already like rather than creating the bends after the purchase. Yes, you can have fun creating a tree with your natural 'talent' and shaping the tree as well, but I have in the past been guilty of buying material that I have no passion for later on. For this reason I now question my purchase over and over again before I commit to it. Don't just buy that genus because it is that genus.
3. Depending on the stock you buy, branch placement may or may not be important. Some trees can be harder to get the right branch placement, so try to purchase material with a lot of branches, as you will always change and chop your mind in regards to the branches as the years go by.
*Give a lot of thought about whether the material shoots back on old wood ; if it doesn't, then consider what the material will look like if it is cut back to the start of the foliage after first styling, and are you really going to be happy with this.
*Try to dig around the trunk and see what is happening. If you are not a fan of reverse taper, this can sometimes reveal its weakness. For me, reverse taper isn't a deal breaker, and in many cases it can look beautiful if done right.
Remember, it is a lot easier to cut branches off than have to create one somewhere.
4. Make sure you are happy with the trunk thickness. If you aren't, grow it long and strong with fertilizer and sun, and don't keep cutting back the whole tree. Once every year or 2 is a good guide if you are building up the trunk. You are only going to thicken the trunk by giving it adequate room to grow and letting the leader(s) grow long and strong without being cut back often.
5. Only buy material that is in good health. Do not buy material that is ill. This isn't a rule of thumb, and I have in the past purchased material that was not in good health. This was because the material was very old and in my eyes it was worth the effort, but I was buying it knowing full well that it may die back significantly or altogether. For a new enthusiast it is much better to learn with healthy stock than sick stock.
6. I never put anything on paper. I never commit to a style. I find it is much, much better to be able to envisage what the tree will look like in your mind with what is presented to you immediately. By this I mean, if you can master the talent of ageing the tree ... say 5 years from now in your mind from what is shown in front of you, this is a far greater resource than constantly referring back to a sketch on paper. Primarily because the tree is constantly changing as it grows, and thus I simply adapt to this change and shape the tree each time I work on it by applying this 2 - 5 year aged visual picture in my mind each time.
Of course I will perform significant cut backs and try to shape it to how I like it, but I find if I stay committed to something early on, then the tree can potentially change so much over the years that it doesn't suit this style anymore. Therefore I have found more so over my experiences that I just work in the moment. Yes, of course I initially do have an idea in mind which is why I purchased the tree, but that can often change depending on what goodness the tree presents me with over time.
7. Keep an open mind! For example with material that shoots back on old wood, always assess the tree before you rub off new buds.
-A bud may form and develop into a second suckering trunk which changes the whole aspect in a very beautiful way. But if you had kept to the sketch you would rub it off as it wasn't to plan.
-After letting your tree grow a strong leader you might find that the increase in height combined with the strong lower foundations now makes for a 'romantic literati'.
If you don't keep an open mind, you miss these opportunities.
8. Try to remember a bonsai is a 3 dimensional organism. Too often you may continually focus on the 'front' and fail to give it any depth or character. Always spin the tree when you work on it and consider the entire 360 degree view before you cut off branches or perform significant bends.
9. Don't focus on what you 'shouldn't be doing'. Concentrate on what makes the tree look better. If it has bar branching, you can usually prune the bar branching and not allow them to grow long. This usually reduces that chances of bulging if it really bothers you. You don't have to correct reverse taper if it looks natural and compliments the tree. You don't have to cut off a large portion of the tree or reduce the height because it has lost a significant branch of your sketched design. (trees can lose branches in nature all the time) Rather, you can just assess if this would make a good feature to the tree before you try to 'work it out of the design'. You also don't have to have branching everywhere, as this also may shade the lower areas and hamper the growth down low.
10. (this is more of a side note) ... Allow the tree to grow with a lot of sun. This is the most under performed step in the life of many bonsai. If you continually cut back and prune the tree every few weeks or so, then you will not only weaken the tree but it will never really grow or put on any significant growth for you to utilize. It will not present you with any decent options and after 5 years you will not have had any real progress on the tree.