Where to begin--setting healthy boundaries
Keep it simple and to the point
When you sense that you need to set a boundary with someone don't feel like you have to explain every detail of why. Keep your explanation simple and to the point.
Example: Your new friend asks you to pick her up but it is out of your way. You simple say, "I'm sorry this will not work for me today. I hope you can find another ride so you can go shopping for the shoes you want." If she pleads for you to still come and pick you up, just simply say. "Sorry, this is not going to work with my schedule today." You give her an open door to continue to push this subject if you make too many excuses.
Example: Someone at church asks you to work in the nursery but you are certain that you have been putting in more than your fair share. You say, "I'm sorry, I will have to pass this time. I've was in nursery recently and feel it is best to say no." This person may press for details, like- when was the last time you worked in nursery etc and you answer back with a simple, "I'm sorry, but I'm not able to say yes at this time." You do not owe them an explanation etc.
Setting boundaries first-/someones feelings come second
You cannot set healthy boundaries and at the same time coddle someones feelings. I'm not saying that you have to trash their feelings but setting the healthy boundary is the primary goal and their feelings on the subject comes secondary.
Example: Your long time best friend wants you to attend their 10th wedding anniversary BBQ picnic and also wants you to bake a sheet cake and decorate it for the occasion. You did this at your other good friend's party and she really liked it and wants it at her party too. In the past you have had trouble saying no to this friend so she just assumes that you will say yes. You answer: "I'm very sorry this is not going to work for me. I'm far too busy this week and decorating a sheet cake would leave me no time for the necessities of this week. I can bring some chips and soda if that would be helpful."
Example two: Your spouse promised his mother that he would come over and cut her grass and promised that you would plant flowers just like you did last year. You, however, made plans to help another friend who just had a baby and you can't do both. You say, "I'm sorry, I can't do it this year...explain in short why...we could do it next weekend but I can't do it this weekend." He is hurt that you won't drop your plans. Just say, you are sorry he feels this way and try to remember that he made the promise without you being aware and you are not obligated to come through on his promises. Smile and tell him you will try to be helpful with more notice.
Set boundaries even if it makes you feel badly
Most people do not recognize that they may assume that you will just jump at the chance to help them out but you need to firmly and lovingly tell them what you are and are not willing to do. You may feel a sense of shame and guilt when you set these new healthy boundaries. This will make it feel like it is wrong to set these boundaries but DO SET the boundaries because people often just do not realize that they are overstepping your boundaries because of a lack of you reinforcing your boundaries in the past. If you have gotten a reputation of being "easy to use" then they don't have much respect for you.
Example: Your long time friend becomes angry because you refused to color her hair tomorrow night. You have simply stated that it will not work for you because you have plans to spend time with your family. She first tries anger and then pouts for 15 minutes. You hate this behavior but do not say anything further. She leaves your presence with a huge huff of air to let you know that she is not pleased. You feel very guilty but know it is for the best to establish these necessary and healthy boundaries.
If you start to set and maintain your boundaries then they will begin to get a sense of respect for you and that will become the new normal. If people start to see that when they ask you to do something and you say no appropriately then when you say yes, they know that this is something that is truly a gift and not just because you can't say no. Strong boundaries make people feel more secure about their relationships. Unclear boundaries led to hurts and feelings of distrust.
Example 2: Your friend asks you very politely if it would work into your schedule to color her hair on a particular date. You see that your schedule is free at that time and you gladly help your friend and feel pleased that she is starting to give you respect.
Red flags for knowing when to set healthy boundaries
When someone whines, complains, uses anger and shovels on the guilt, these are red flags that you KNOW that a boundary must be established. Other indicators might be feelings of being suffocated, swallowed up, overwhelmed and that feeling like you will have to run away to get any peace. It might take getting angry before you are ready to set healthy boundaries but if you set the boundaries early on then you save yourself loads of grief and even physical symptoms of stress (headache, stomach knots, panic and depression) Setting healthy boundaries will save you from feelings of resentment and guilt for later on abandoning this person totally because you could not take the drama any longer.