When you do a jigsaw puzzles, you have to start from outside in. Choose the edge peices which have straight edge. After select border pieces, then you can start.
You also have to look for the peice that has similar shade of color.
How I Do Jigsaw Puzzles
This is not necessarily a step-by-step of how to do a jigsaw puzzle, but I know that I do puzzles very well, quickly and easily, and I thought I would share some observations of my own process
Puzzle boards
I recommend you acquire a board on which to do your puzzles. This can be cardboard or wood, but it needs to be smooth, large enough to fit your puzzles on it, stiff enough to lift and slide around, and preferably of one uniform color.
Getting Started
I start with the edge of a puzzle. This is usually a large part of the puzzle, and the pieces are easy to find among the other pieces. Sometimes, but not always, I sort through all the pieces of a puzzle, looking at them all, leaving them facing up on the puzzle board and picking out the edge pieces and other pieces I find striking. Group these other pieces according to pattern. Sometimes it's easier to select in subcategories than to sort after you have a pattern group collected, so if you notice some size or tint variation in the pieces you're collecting, be sure to save them separated according to subcategories.
When all else fails, sort by shape. Puzzles vary a lot as to how useful this is. I've done puzzles that had pieces shaped like animals, and other puzzles where there were probably only 10 unique types of piece shape in the whole puzzle. If there are pieces with a unique curve to the side, or pieces with unusual configurations of interlocking parts, those are usually the easiest ones to start with.
It is my belief that as I sort through pieces I register them in some not-entirely-conscious catalogue so that when I see the match to a piece I'm fairly likely to recognize it.
The other part of finding a piece that fits involves imagining what a piece looks like according to the surrounding pieces. This includes Visualizing negative space, filling in and extrapolating patterns. You may not be able to figure out what the whole piece looks likes, but you can imagine the edge, or some dominant characteristic, like color or figurative content (e.g. green line, or an eye) that you can then serach for. For most puzzles, if all side of a piece are determined by the surrounding pieces being present, you know what it looks like. To do this well, you need to be able to hold and rotate an image in your head.
Alignment
Often there are hints to proper alignment of the pieces. Light sources or shadows are sometimes a strong indicator. The pieces might also be longer in the vertical direction than in the horizontal. Some shapes have natural alignments (flowers, people, houses). If the puzzle has text on it, the text may consistently be aligned in one direction, as in a map. I once did a puzzle called Shooters, which was a sea of marbles, mainly by first going through and turning all the pieces so that they were aligned the same way according to the highlight.
To Look or Not To Look
Philosophies vary as to whether or not one should refer to the cover illustration while working on a jigsaw puzzle. I personally started out looking at them a lot (that one with marbles I mentioned before would have been almost impossible otherwise) but lately I find it so easy to locate exactly where a piece goes (provided it has any distinguishing markings on it at all) that it seems like cheating. And I know some good family friends who hold that it is always cheating.
I mostly just refer to the box illustration now to determine the general position and orientation of large blocks of pieces, once assembled.