One aspect of your plans and strategies might involve bowling from different points on the crease at either the start of your spell or when you're bowling to a new batsman after a dismissal.
Scroll through the video to about 12 mins and 30 seconds
Double click on the image
to open the video in Youtube.
My own approach involves writing notes and speaking to the batsmen and players after the game about these aspects. I take it a step further in that I try and photograph the players and then produce my own wagon wheels of the players scoring zones like this...
*Click on the image to go to the website.
I then add a suggested fielding plan for the batsman for the next time I bowl at them.
Shane Warne's advice
If you scroll through the video to about 12 minutes and 30 seconds Warne starts discussing different approaches and tactics for bowling at left-hander's. But, the same advice is applicable to right-hander's or anyone at the start of your spell or when a new batsman comes to the crease you've never bowled against.
The basics premise is that you should explore the batsman's strengths and weaknesses, so Warne suggests that you move around the crease bowling your stock leg-break - especially if you've just come to the crease. What this means is...
If he blocks and looks tentative/cautious, I'd bowl the same line but a little shorter looking to get the edge with one that spins a little more (Spin it harder or squarer or a combination of both).
Depending on what happens - and how much the ball does or doesn't turn I'd move wider on the crease to position (5) and see how that works - does it trouble him/her more does it offer any advantages. I might then bowl a couple more from over the wicket changing the flight, length or speed - still bowling the stock ball making sure I'm bowling okay and able to maintain a degree of control. If I'm back on strike with the same bloke I might go around the wicket - changing the field perhaps to one with more protection on the leg-side - dependent on how well he looks to have played the other bowler - remember always watch what the batsman does with the other bowler in between your overs. It may be you've already established that he/she is average on the off-side and then when the next bowler gets his chance to bowl at him you watch him get hit for 4's and 6's on the leg-side! You might want to adapt your plan at this point and bowl of the off-side!
The other thing people often don't consider is the depth of the crease. if you're bowling a nice length and you struggle to adjust your lengths bowl off a different length if you're looking to drop it shorter e.g. from position (1)?
I'll apologise now for the Youtube link not working SKY are ruthless at hunting these vids down and making the up-loaders delete them. Then they wonder why cricket is dying out.
The truth about the nonsense you all call 'Sliders' https://www.youtube.com/watch?v=M9sifVFMJVc&t=333s
And this one Ian Bell - "Natural variation" https://www.youtube.com/watch?v=b3VnK2KLRds&t=43s