Portion size - DO NOT PANIC!!!! As long as you only eat until you are full (not stuffed) the plan will work. Do not use other people to judge YOUR portion size - only YOU know when you have had enough.
Plan. Have a look in your book or on-line to find the best choices to eat when you're out. Don't wait until someone asks you out for a meal, do it NOW. (That way you won't have to go hunting for your book to check!! Nothing worse than an impromtu dinner invite when your books are at home!!)
I have a little bag with some low syn treats (ready for the cinema!). Just throw it in my bag at weekends (when I'm most likely to end up at the cinema) - just in case!!
If you're cooking, batch cook and stick the extra in the freezer. It's great for those days when you're feeling too tired to cook or get home late.
As for syns, as long as you are having between 5-15 syns a day (most people aim for about 10), you are following the plan. Obviously if you are having more than 15 syns per day (unless authorised by your consultant) this may affect your weight loss. The two main reasons for people going over their syns (accidentally) are not weighing and measuring accurately and not checking syns first.
DO NOT GUESSTIMATE your healthy extras or syns. If you're having sauces - use measuring spoons - and make sure it's a LEVEL spoon (not heaped!).
IF YOU DO NOT KNOW THE SYNS OF SOMETHING - CHECK FIRST!!!! Once you've eaten it, you can't take it back. The number of people who say 'I've just eaten XYZ and just checked - OMG! It was 18 SYNS!!! I never would have had it if I'd have thought it was THAT much!!!'
If you are really worried that you won't lose any weight (following SW 100%), then keep a food diary. You should have 4 weeks worth in your starter pack. This is one of the most important things to do, so that your consultant can check (if you're having any problems or have a disappointing weigh in).
HTH
(Not quite seasoned but liberally coated in Malt Salt)